A Vascular Flora of the Selkirk Mountains, Bonner and Boundary Counties, Idaho

The vascular flora described here covers ∼2295 square kilometers (∼886 square miles) of the Selkirk Mountains that lie in the Idaho Panhandle, covering an elevational range of 540–2330 m (1770–7670 ft). The majority of the mountain range is underlain by granitic rock of the Kaniksu Batholith, and is diversified by the rich glacial history of the Panhandle. The study area contains multiple pockets of alluvial and glacial deposition that serve as specialized habitat for present-day floristic diversity within the range. The Idaho Selkirks are part of the Northern Rocky Mountains and have floristic influences from the Pacific coast, boreal north, the Columbia Basin, and the RockyMountains to the south and east. Despite notable collection interest over the last century in the northern Idaho Panhandle, a comprehensive checklist did not exist prior to this project, and previous collecting efforts were uneven, creating significant gaps in coverage and incomplete documentation of the area. A total of 108 collection days were spent in the field in 2019 and 2020, resulting in 4155 vascular plant collections from 665 collection sites, documenting 845 total unique taxa in 94 plant families. Taxa previously collected but not recovered were first verified by the author using historical specimens housed at multiple Pacific Northwest herbaria, and were then included in the final checklist. Sixty-two rare taxa and six state collection records were found in the study area, as well as numerous range extensions and county collection records. While the primary objective was to document and voucher all vascular plant taxa of the Selkirk Mountains of Idaho to create an annotated checklist of the vascular flora, additional objectives included formal assessments of the vegetation types and threats to the flora of the study area, as well as increasing documentation of sensitive, rare, and non-native species occurrences within the range.

introduction For centuries, floristic inventories have been one of the greatest drivers of botanical discovery, and continue to provide the basis for intersectional studies in systematics, taxonomy, and evolution (Ertter 2000). However, the impact of plant collecting is often understated, as seen in its recent decline (Prather et al. 2004), despite expansion of known biodiversity, as well as increased modern applications for documented biodiversity (Heberling et al. 2019).
While botanical collections in Idaho date back to 1806, compared to surrounding states, Idaho has seen less collection coverage (CPNWH 2020). Prior to this study a "floristic hole"-a geographic region lacking adequate collection effortcharacterized the Selkirk Mountains in the northwest tip of the Idaho Panhandle. The Selkirk Mountain range lies within the Northern Rocky Mountains, and is composed of north-south trending mountains from southeast British Columbia into the northernmost portion of the Idaho Panhandle. Despite the region's rich history of botanical interest and diverse species assemblages, no comprehensive systematic botanical inventory had occurred for the Idaho portion of the range prior to this study. With no prior baseline assessment of the vascular plant diversity of the region, the Idaho Selkirks were well suited for floristic inventory, as conditions for natural areas continue to experience anthropogenic influence (e.g., introduction of non-native taxa, climate change, anthropogenic disturbance; Heberling et al. 2019).
While this baseline study serves as the flora for the region defined herein, it also serves as a model for comprehensive floristic inventories. This study utilized satellite imagery, tablet or smartphone app-based collecting notes, and the integration of existing digitized collection records into the treatment. Additionally, in targeting an area enjoying abundant recreational usage like the Idaho Selkirks, a subsequent goal was to increase usership of the flora document. Supplementing the flora with scientific illustrations of charismatic species will ideally expand usership through visual enhancement. Finally, this flora includes a comprehensive social and natural history background, with the goal of acknowledging interdisciplinary pieces of the floristic puzzle. Together, these twists on the traditional flora help to provide the most comprehensive flora of the Selkirk Mountains of Idaho to date.
Objectives.-The primary objective of this floristic inventory was to catalog and voucher all vascular plants of the Selkirk Mountains of Idaho, with the goal of producing an annotated checklist. Additional objectives included assessing the vegetation of the mountain range, collecting comprehensive distribution data, and assessing current threats to the flora. Lastly, focal inventory goals included documenting sensitive, ALISO Faust,Legler,and Tank Fig. 1. Predominant land ownership in the study area. Dark gray signifies National Forest, medium gray signifies Idaho Department of State Lands, and parcels not labeled are private holdings. Map Source: IDL (2020). threatened, rare, and endangered species, as well as non-native species occurrences.
Physical Setting of Study.-The Selkirk Mountains of Idaho are defined using a combination of political, ecological, natural, and anthropogenic boundaries ( Fig. 1-Fig. 9). The political boundary of the United States-Canada border defines the study's northernmost boundary. While the Selkirks run south to north, well into British Columbia, Canada, the floristic survey herein focuses exclusively on the portion of the Selkirks that lie in Idaho, hereafter referred to as the Idaho Selkirks. The boundary to the east is the Kootenay Valley Floor (Fig. 3) as it edges to West Side Road, which parallels Highway 95 as the boundary heads south, to the valley's southernmost extent at Lake Pend Oreille. From Lake Pend Oreille and Highway 2, the southern edge follows the base of the mountain range as it edges west along the Pend Oreille River. The southwestern edge is bounded before the town of Priest River and continues north to Coolin, following the base of the mountains east of Priest River itself on East Shore Road. From the southern end of Priest Lake in Coolin, ID, the boundary continues north as it follows Priest Lake, towards Upper Priest Lake (Fig. 7). The western edge continues north as it follows the Upper Priest River valley north to American Falls and Kaniksu Mountain, which serves as the westernmost point of the study area. Ownership of the area is split between three main entities, the Kaniksu National Forest, Idaho Department of Lands (IDL), and private ownership. The study area encompasses ∼2295 square kilometers (∼886 square miles). natural history

Physiography
The Selkirk Crest.-The Selkirk Crest is the central point of the study area. It contains 18 named peaks, with Parker Peak the tallest at 7670 ft (2338 m), with a dramatic descent on the eastern side where it meets the Kootenay Valley (Fig. 8). The crest consists of granitic monoliths including Chimney Rock, Lions Head, and Mt Roothaan (Fig. 2 and 4). Subtending the crest are glacial valley basins that descend into low gradient streams on both sides. The west and south sides of the crest are characterized by a more subtle relief, as the mountains descend towards Priest Lake and Sandpoint/Lake Pend Oreille, respectively.
The Kootenay Valley.-The Kootenay Valley at the eastern base of the Idaho Selkirks is characterized by agricultural lands and wetlands, and is a natural border for this mountain range as it meets the dramatic steep slopes on the eastern side (Fig. 3). This area is the lowest elevation of the study area, with Bonners Ferry at 1896 ft (578 m). Additionally, the valley floor divides the nearby mountain ranges, the Purcells and the Cabinets, from the Idaho Selkirks, peaking at similar elevations. The valley floor is home to an entirely different assemblage of species, dominated by agricultural introductions and wetlands, and is considered glacial outwash bottom lands (Alden 1953).
Priest Lake.-Priest Lake provides the western boundary of the Idaho Selkirks and modest relief west of the crest. This lake was formed partially by the Newport fault, which contributed to forming the basin that subsequently gave way to Priest Lake. Following the fault's movement, the basin was filled by the Cordilleran Ice sheet from Canada, resulting in a glacial moraine (Fig. 7;Alt and Hyndman 1989). Erosion on the west side of the crest subsequently melted and filled the depression that the ice sheet carved out. This lake is one of the low points in elevation for the Idaho Selkirks at 2439 ft (743 m).
Lake Pend Oreille.-The western edge of Lake Pend Oreille and its outlet into the Pend Oreille River that flows into Washington serve as the southernmost boundary for the Idaho Selkirks. The lake was formed by glaciation and scouring from the Missoula floods. At 1158 ft (353 m) deep, it is the deepest lake in the state, and sits at an elevation of 2067 ft (630 m) (Alt and Hyndman 1989).

Geology
The Idaho Selkirks are visually defined by the aforementioned physiography, which are present-day reminders of multiple geo- logic processes that began billions of years ago. However, the geologic story here begins with what geologists refer to as the Belt Supergroup Formation. The Belt Supergroup is a complex of majority meta-sedimentary rock, composed of metamorphized sediment, found in eastern Washington, northern Idaho, western Montana, and extending north into Canada, formed between 1.45-1.40 billion years ago (Maley 1987).
This Belt Supergroup Formation is often defined by the movement in and around the belt formation, referred to as the Priest River Complex (Doughty and Price 2000). The Priest River Complex is composed of the transition zones of the Purcell Trench Fault to the east and the Newport Fault to the west, with the Spokane dome to the south near Sandpoint, ID (Doughty and Price 2000). The Purcell Trench, composed of Precambrian Supergroup belt formations, was weakened during the Precambrian period (between 4.6 billion and 541 million years ago) by what has been hypothesized as granite magma rising into the crust of northern Idaho, which moved the upper slab of this trench east through massive uplift (Alt and Hyndman 1989). This led to the thickening and uplift of the Selkirk crest, which had been weakened by prior fault activity (Alt and Hyndman 1989). This specific movement defines the different geologic makeup of the adjacent Purcell and Cabinet Mountains, which are composed of belt sedimentary rock-rock that used to lie atop the Selkirk Mountains long ago. This large fault movement left behind largely igneous, meta-sedimentary granitic rock or granodiorite-also known in this area as the Kaniksu Batholith (Fig. 10). The majority of the Idaho Selkirks is composed of nearly homogenous younger granite rock formed during the Cretaceous period, accompanied with young alluvial deposits, while the areas in the north and to the east of the Idaho Selkirks are composed of younger meta-sedimentary rock (Lewis et al. 2012).
What is left of the Purcell Trench today is the Kootenay Valley, where sedimentary rock slid over metamorphic rock, leaving a large trench behind. However, the Kootenay Valley, Vascular Flora of the Selkirk Mountains, Idaho Fig. 9. Elevation gradient for the study area. Map source: INSIDE Idaho (2020). equivalently referred to as the Purcell Trench, is the result of both carving from multiple fault movements, as well as glacial activity that sculpted the charismatic valleys and lakes of northern Idaho (Alt and Hyndman 1989).
The geology of the Idaho Selkirks is a mix of both geologically recent and older events that shape the study area and define the floristic make-up. During the most recent ice age which occurred in the Pleistocene (2.6 million years to 11,700 years ago), ice crept down from Canada on both sides of the Idaho Selkirks, forming both Kootenay Valley and Priest Lake (Alt and Hyndman 1989). The southward movement of the Cordilleran Ice Sheet occurred during multiple episodes, with advances and retreats correlating to shifts in climate (Alt and Hyndman 1989). There is additional evidence of alpine glaciation during the Pleistocene that took place after the ice sheet retreated (Maley 1987).
Subsequently, the two main types of glacial activity that occurred in the area are deposition and erosion, products of predominantly ice sheet glaciation and sparse alpine glaciation or snow accumulation (Alden 1953). Deposition, the process of sediment settling into the landscape, was a product of the continental ice sheet creeping south. Its movement rounded many of Fig. 10. Geologic units for the study area. The legend is organized from oldest to youngest rock type. Map source: USGS Idaho Geological Survey (Lewis et al. 2012). the softer hills on the west side of the Idaho Selkirks (Alt and Hyndman 1989). The ice sheet movement left behind till and outwash, a composition of mixed sizes of sediment, including clay, sand, and gravel, containing high organic material in areas of erosion. Erosion, resulting from alpine glaciation, typically scoured the landscape and left behind dramatic rock faces or moraines (Savage 1967). What is left behind are extreme slopes and descents, as seen on the east side of the Idaho Selkirks, as well as on the charismatic crest (Alt and Hyndman 1989). Erosion occurred in areas of high sedimentation that resulted in river terraces and benches at lower elevations, as seen around Upper Priest Lake (Smith and Weitz 2015). While much of the Idaho Selkirks is uniform granite, pockets of glacial activity where deposition and sedimentation occurred consist of high organic material and diverse flora, discussed further in the Vegetation Types section below.

Soil
The soils in the Idaho Selkirks were initially formed from the belt series; the parent material composed of fractured rocks with many coarse fragments that lies under glacial outwash and deposition from glacial lake Missoula (Savage 1967). Accompanying the coarse fragments are remnants of volcanic ash from past volcanic activity within the vicinity, most significantly from Mt. Mazama 6700 years ago. The volcanic ash is largely amidst stony soils where coniferous forests reside, and contributes to increased forest productivity (McGrath et al. 2002).
The glacial history of this area has affected what we see both above and below ground in the Idaho Selkirks. The soils in the area are considered "youthful and immaturely developed" due to more recent glacial activity and alluvial deposits (Savage 1967). While most of the range consists of granitic batholith, composed of less fertile soil material, pockets of alluvial deposition also reside in the area (Savage 1967).
Alluvial soils are commonly characterized by high organic matter and high fertility, formed by moving water depositing soil, typically made up of silt, clay, sand, or gravel (Maley 1987). These areas consist of distinctive vegetation types, such as peatlands or mesic forests, pocketed within areas flooded by coarse alluvium. Overall, alluvial soils contribute to a small percent of soils within the study area. The majority of soils within the range are more stony and less fertile, supporting more homogenous and widespread forest types (Daubenmire and Daubenmire 2002).

Climate
The Idaho Selkirks are characterized predominantly by a maritime climatic influence (McGrath et al. 2002). The maritime influence is a product of the prevailing westerlies, a weather pattern that moves coastal moisture inland from the Pacific Ocean (Cooper et al. 1991). This weather pattern begins in British Columbia and continues south into the Clearwater area of central Idaho (Cooper et al. 1991). The study area's climate is also attributed to its inland location, with patterns deemed intermediate between the coast and the conditions east of the Rocky Mountains (Tinkham et al. 2015). However, the climate can vary from ridge to ridge, influenced by continental and boreal weather systems, and therefore contains an array of diverse microsites within the study area (Nicholls with Mellen 2014). On top of such variability, a west-east moisture regime is found throughout the study area, typically wetter on the western side of the mountains and drier on the eastern side of the range, which works alongside a typical elevation gradient in temperature and moisture (Lucid et al. 2016). The dynamic nature of the study area's climate is likely due to the wide range in elevation and topographical features characteristic of the range.
The majority of the precipitation in the Idaho Selkirks comes in the form of snowfall, with snowfall possible in any month of the year (Nicholls with Mellen 2014). The southern tip of the range gets the least amount of snow, with snowfall increasing steadily at higher elevations and northern localities (Fig. 11). This weather pattern contributes to long winters and brief growing seasons, where winters are relatively cold and summers are generally mild. This climate is fairly temperate compared to the Rocky Mountains, and allows for a diversity of ecological habitats. The summer months of July through September are the driest months, August being the driest and warmest month, averaging 16°C, with monthly average highs of 24°C. The cold and wet Fig. 11. Snowpack. Normalized ground snow level for the study area, in pounds of snow per foot (psf). Map data source: INSIDE Idaho (2020). months occur between October to March, while April to June generally accommodate more pleasant yet still variable weather. Precipitation can vary year to year; however, November is the wettest month with an average precipitation of 176 mm, with highs in the last decade well over 400 mm precipitation (PRISM Climate Group 2004;Tinkham et al. 2015). The winter months are characterized by harsh, cold weather and December is the coldest month, with temperatures averaging -4°C (Fig. 12). However, the area is well known for the ability to have belowfreezing temperatures throughout the year (Tinkham et al. 2015).

Disturbance History
Following the latest ice age, natural forms of disturbance from extreme weather events were the primary forms of disturbance until anthropogenic disturbance began in the 20 th century. Despite the maritime climate, the months of July, August, and September welcome lower precipitation, and lightning storms can be prevalent (Cooper et al. 1991). While major summer fires have occurred in both low and high elevation fire regime groups, landscape change from fires has been largely temporary, with Vascular Flora of the Selkirk Mountains, Idaho Fig. 12. Average monthly temperature and precipitation from 2009 to 2019 for the study area. Monthly precipitation for the region is given by vertical bars, and monthly temperatures for the region are given with lines. Data are drawn from two weather stations from both the west and east sides of the mountain range. Graph data source: PRISM (2004). strong regeneration due to the presence of high organic matter (Daubenmire and Daubenmire 2002).
In drier forests within the Idaho Selkirks, Pinus monticola was historically more prevalent before the spreading of white pine blister rust, Cronartium ribicola, in the 1950s (Graham 2004). While P. monticola has been shown to regenerate, succession and regeneration from fire continues to change the vegetation makeup over large swaths of the mountain range. Besides tree mortality, the biggest effect from white pine blister rust, has been seen in hydrology. With the loss of this dominant tree cover on the landscape, snow melt happens earlier and faster, which can dredge the landscape, and contribute to earlier flowering time in areas once inhabited by P. monticola stands (Tinkham et al. 2015).
The greatest impact on the study area has been, and continues to be, in resource extraction. Alongside private timber and National Forest silvicultural operations, the state of Idaho secured land on the east side of Priest Lake, now known as the Priest Lake State Forest, a part of the Idaho State Endowment Lands, managed by Idaho Department of Lands. This land was secured in 1911 at the suggestion of John Leiberg during the establishment of Idaho's statehood, and land originally destined to be managed by forest service, was given to the state to manage timber operations for the purpose of supporting public education in Idaho. This portion of the study area has been harvested continuously for timber since 1917 to generate funds for public schools in Idaho (Smith and Weitz 2015). Logging and private development continue to be the main form of disturbance to the mountain range in the last century, creating heterogenous landscapes within the low-to middle-elevation mixed conifer forests on all sides of the range.

Pre-Contact Inhabitants
The study area described here lies in unceded Ktunaxa (Kootenai) and Qlispé (Kalispel) territory. Two main Indigenous Groups, The Kootenai of Idaho and The Kalispel Tribe of Indians, overlap within their historic territories of northern Idaho, yet have separate and distinct tribal organizations, cultures, languages, and histories (Anna Armstrong, The Kalispel Tribe of Indians, pers. comm. 2020;Walker 1971;Fig. 13).
The Kalispel people were migratory, and historically traveled to areas around Priest Lake and the southern end of the Selkirk range for seasonal harvest journeys of both flora and ALISO Faust,Legler,and Tank Fig. 13. Indigenous territory for predominant tribes in the study area. Map data source: Native Land (2020).
fauna (Smith and Thompson 1961). The Kalispel traditionally traveled over what is now Baldy Road near the Sandpoint entry to the mountains, to get from the eastern valley floor over to the western side of the mountains where Priest Lake lies (A. Armstrong, pers. comm. 2020). The Kalispel were subsistence gatherers and relied on the waterways for whitefish and hunted in the mountains for deer, elk and moose. Plants were gathered in the valleys and mountains for building, food, and medicine; one plant of particular importance was Camassia quamash, Camas (A. Armstrong, pers. comm. 2020;Fritz 1997). They historically maintained base camps along the Pend Oreille River, ntx w e, and Lake Pend Oreille, Qapquape, for the winter, and regularly traveled for harvest between spring and fall throughout their historical territory (A. Armstrong, pers. comm. 2020).
While the Kalispel generally occupied the southern end of the study area, the Kootenai, sometimes referred to as the Bonner's Ferry Kootenai, were predominantly established along the Kootenai River system further north (State v. Coffee 1976). Plant stands were regularly tended and used for sustenance, preservation, building winter camps and canoes, fiber, medicine, and ceremony for thousands of years. Kootenai harvest techniques were low impact on the landscape, and neither tribe has a recorded history of ecological land tending (Smith and Thompson 1961). However, much of the history and culture of both tribes is not comprehensively recorded and much of it has been subsequently lost (A. Armstrong, pers. comm. 2020).
The Kalispel recorded the first encounter with settlers in 1809 (Smith and Thompson 1961). Missionaries soon followed, and quickly began to colonize the area and push the Kalispel out of their seasonal lifestyle and cultural heritage and towards the church (Smith and Weitz 2015; Elders of the Kootenai Nation 1990). Ultimately, maps made their way east and before long, surveyors flocked to the area. Settlers quickly began using antiindigenous narratives of the Kalispel in the region, and by the end of the 1800s, settlers who felt threatened responded by forcefully and violently taking Kalispel land, which ultimately lead to Kalispel extraction from their traditional lands.
Today, the Kootenai and Kalispel both are federally recognized tribes, a part of the Salish Confederated and Kootenai Tribes of the Flathead Reservation, despite not having access to their original territories (Ruby and Brown 1986).

Post-Contact Inhabitants
Settlers began to visit and colonize the area in the 1800s, with the first recorded contact with David Thompson in 1809, followed by missionaries (Smith and Thompson 1961). Missionaries were then followed by loggers, miners and settlers. Due to the intensity of winters in the Idaho Selkirks, and densely forested lower elevations, anthropogenic land use by non-indigenous settlers was concentrated initially in the valley floor and lakeside, as opposed to the mountain range. By the mid 1800s, enough white people had come through the area that the majority population was no longer indigenous (Elders of the Kootenai Nation 1990).
Until the railroad was built in the early 1900s, the area contained low human population (Smith and Weitz 2015). At the turn of the century, with new mining occurring near Priest Lake, and the advent of more efficient logging, the area became quite popular, both with homesteaders and those seeking jobs in the extraction of minerals, timber, and water. In 1907, the National Forest system was established, and what was the Priest Lake Forest Reserve became the Kaniksu National Forest (Smith and Weitz 2015). In 1911, the Priest River Experimental Forest was established, to aid in the study and practices of silviculture in the region, and at the same time Idaho Endowment Lands were secured and excluded from the Kaniksu National Forest purview (Graham 2004). The exploration, settlement, and resource extraction by white settlers in this rugged landscape would not have been possible without the coercion and forced guidance of the indigenous peoples out of their traditional homelands (Smith and Weitz 2015).
On top of a century of timber harvest, there is also over a century-long history of tourism in the area, starting in the late 1800s, when white settlers advertised the area as 'rugged' and 'wild', and hired Kalispel people to guide social elites from the east coast around the range (Smith and Weitz 2015). The reputation of the Idaho Selkirks as rugged and wild has persisted into recent times, and tourists come to the area to visit Priest Lake, hike in the Kaniksu National Forest, and to enjoy winter sports at Schweitzer Mountain Resort.
In recent history, this area has been inhabited by notable white supremacists and members of the Aryan Nations (Balleck 2018). The towns within the study area vicinity maintain a palpable social and cultural climate of modern white supremacy, while social diversity and representation of the area's indigenous history are notably less prevalent. Reminiscent of the region's colonial history, the Idaho Selkirks were named after the Fifth Earl of Selkirk, Scotland, Thomas Dougal, a wealthy member of the European elite. The name is rumored to have been applied by fur trader David Thompson, who originally named the range the Nelson Mountains; however, he changed the name to Selkirk Mountains to honor Dougal who at the time was an enterprising patron of a large mapping company (Boone 1988). In order to confront white supremacy within this region and in floristic endeavors, it is imperative to begin with acknowledgement of the history of colonization not just of the region, but of the history of botanical pursuits (Lagomarsino and Frost 2020).

Historical Botanical Collecting
Botanical collecting in the northern Idaho Panhandle began at the turn of the century. John Leiberg was one of the first botanists to collect on the Panhandle, obtaining the first known collection records from the Priest River Forest Reserve area in 1897 (GBIF 2021). Following Leiberg, botanical records for the study are from 1901, comprised of single collections of ubiquitous species from Priest Lake, and lack comprehensive metadata, a feature of many older specimens (CPNWH 2020). Collecting of the area increased after 1911 (CPNWH 2020), with the establishment of the Priest River Experimental Forest (PREF) in the southern portion of the study area. Collections there were intended to document common forest species assemblage before large scale forestry began in the adjacent Idaho Endowment Lands. The majority of historical collections in the study area (Table 1) are concentrated at PREF and were made before the 1980s.
Notable contributions to the area continued with John H. Christ, who began collecting in the early 1920s alongside Henry Rust, both collecting for general discovery. Rexford F. Daubenmire was the first major collector in the area in the 1940s, who surveyed with the goal of vegetation typing northern Idaho for the Forest Service. Daubenmire's collections were concentrated at PREF, as well as along the Selkirk Crest. At the same time, notable Pacific Northwest botanist C. Leo Hitchcock and his students made a handful of collections in the southern range of the Idaho Selkirks, which were used to produce the Flora of the Pacific Northwest (Hitchcock and Cronquist 1973). Following Daubenmire's interest in the area, William Baker began collecting throughout Idaho, including scattered locations within the study area (CPNWH 2020).
Notable University of Idaho botanists, Douglass Henderson and Fred Johnson, began collecting in the late 1960s. Henderson's and Johnson's collecting focused on locating and researching prominent coastal disjunct and rare species in the Idaho Selkirks and surrounding mountain ranges. Peter Stickney, notable Forest Service botanist, collected throughout the range in the late 1960s through the 1970s. However, some of the most significant collections for the region were made in the 1980s by Robert Bursik, who ventured into previously unexplored habitat on both sides of the Idaho Selkirks. Robert Bursik made significant collections of fen species assemblages, both for his master's research on the peatlands of northern Idaho, and subsequently for the Forest Service and Idaho Department of Fish and Game. Bob Moseley, who worked alongside Bursik, also was contracted by the Idaho Conservation Data Center to collect throughout Idaho. Pamela Brunsfeld, former University of Idaho Stillinger Herbarium Collections Manager, and associated collectors were the last major botanical contributors to the knowledge of the area in the early 2000s. Brunsfeld's focus was on general floristics of northern Idaho (P. Brunsfeld, pers. comm. 2019). In reflecting on the century of collecting, nearly every other decade there were efforts to collect in this mountain range (Table 1).
Despite the estimate of ∼2800 vascular plant collections that represented the area prior to 2019, previous collections were concentrated in accessible areas, and holes remained throughout the range (CPNWH 2020). It is difficult to synthesize the known taxa prior to this study, partly due to vague specimen locality data, and partly because voucher specimens from this area are distributed across ten herbaria, including CIC, EWU, ID, MONT, RM, SRP, UBC, USFS, WS, and WTU (acronyms according to Thiers 2021). A considerable portion of the historical collections in the area contained misidentifications, and a large subset contained verifications holding outdated nomenclature. Further notes on annotation are included in the Checklist and Methods section below.

Fieldwork
Fieldwork was completed over the summers of 2019 and 2020 based out of Sandpoint, Idaho. Collection sites were identified based on accessibility/road access, history of prior collecting, moisture gradient, aspect, elevation, disturbance history, and representative vegetation type/species assemblage. Serendipitous collecting on roadsides occurred in between visits to less accessible sites. A notable barrier in the Idaho Selkirks is restricted access to gated grizzly bear habitat, with limited entry managed by U.S. Forest Service officials. Only two visits were permitted beyond the gates during the study.
Collection sites were chosen weekly based on the aforementioned characteristics, focusing on one of the four quadrants of the mountain range each week-NE, SE, SW, NW. Sites were generally visited in elevation bands, working in the earlier field season at lower elevations, then up to high elevations by mid-to late field season, following phenology. At the end of each field season, collecting occurred again at low elevation, with a focus on aquatics and Asteraceae.
After identifying each collection site, the site was surveyed with the meander search technique (Hartman et al. 2011). The majority of the collecting in this effort was far from trail and roads, unlike most previous collection efforts. This technique allowed for thorough yet efficient surveys while hiking and camping. Plants were collected using digging tools and put into individual plastic bags, stored in backpacks, or put into modified field presses, until returning to base camp. At camp, specimens were pressed or transferred into full standard herbarium plant presses at the end of the day. Plants were then dried in a plant drier upon return to the field station, before returning to the Stillinger Herbarium (ID) for processing, where the full set of specimens is deposited.
Plants were predominantly collected in unicate, except for species of interest. However, all initial collections made during this study were collected in duplicate or triplicate. To add to our understanding of species distribution within the range, repeat species were collected at each vegetation type in each available phenology. This method allowed capturing variable species morphology, and increased coverage of undercollected infraspecies. However, as the field season extended and more ground was covered, not all species observed were collected at every site. This was partially due to lack of desired phenology ALISO Faust, Legler, and Tank  being present, but additionally due to a selective sampling approach. Selective sampling was used particularly in the late summer and fall portion of each season where taxa were targeted. Depending on the focus of the survey and weather conditions, surveys ranged in size from less than an acre up to 14-mile hikes with multiple collection localities throughout the route taken (Fig. 14).

Data Capture
At each collecting site, a locality and site description were taken prior to collecting. Site and specimen data were recorded using a "Field Notes" mobile app, currently in beta testing. The user interface of this mobile app is directly tied to the University of Idaho Stillinger Herbarium database and the Consortium of Pacific Northwest Herbaria data portal (Fig. 15;B. Legler,unpubl.). In this app, the user creates numbered collecting sites that include GPS coordinates, locality description and site description, and then attaches collections to each site. Under each collection, one can quickly record specimen information (e.g., collection numbers, tentative identifications, specimen notes, phenology).
Upon return to internet access, the user uploads these field notes directly to the Stillinger Herbarium database. This app was installed onto a Samsung Galaxy Tab A Tablet for field use for the 2019 season. Legler developed iPhone compatibility for the app in 2020, allowing it to be used as a browser-based mobile app with a personal iPhone for the remainder of the 2020 field season. The tablet and mobile phone were treated like a collecting book, additionally being used as a GPS/navigation device, camera, and library for all field resources. Additionally, a GPS data logger was used, with the intention of supplementing all collection GPS way points by recording routes traveled (Fig. 14). Finally, tissue samples of nearly all species documented during the study were collected in the field. A small portion of every taxon collected was placed in silica gel desiccant to add to an expanding tissue collection for future genetic analyses, housed at the Stillinger Herbarium.

Herbarium Work
Identification took place both in the field and in the herbarium. At the end of each field season, plants were organized into families and keyed by group using an amalgamation of sources. Specimen identifications were verified using Flora of the Pacific Northwest (FPNW; Hitchcock and Cronquist 2018), Flora of North America (FNA 1993+), The Jepson Manual (Baldwin et al. 2012), Sedges of the Pacific Northwest (Wilson et al. 2008), primary literature and reference collections currently housed at ID. All specimens collected during the study are housed at ID, and are publicly accessible through the Consortium of Pacific Northwest Herbaria data portal (www.pnwherbaria.org). The source used is noted on every specimen. All collections made during the study were identified by the first author, unless otherwise noted.
The Consortium of Pacific Northwest Herbaria data portal was used to obtain prior historical collections for the area (CP-NWH 2020). A polygon was drawn for the study area, and all collections for that area were exported from the portal. The polygon export was initially examined for specimens that were incorrectly georeferenced, mislabeled, and/or misidentified, and invalid specimens were removed from the export. To supplement for incorrectly georeferenced specimens, notable collectors were individually queried for collections in the study area. After identifying taxa not collected in this study, nearly 300 putatively unique taxa were identified for further validation. From this set, specimens were tagged based on the following categories: nomenclatural and taxonomic updates, vague localities, and remaining database errors. Finally, an unmounted backlog of specimens from Robert Bursik was evaluated for all species found within the noted study area, and added to the checklist if verified. Every specimen not relocated was verified or annotated, resulting in 77 historical collections not collected in 2019 or 2020. Historical collections were examined from ID, UBC, WS, and WTU, and all identifications were verified by Faust.

Vegetation Types
While broad vegetation types of northern Idaho exist (Daubenmire and Daubenmire 1968), these were described to guide silvicultural practices. Daubenmire's classification identifies vegetation types at their climax stage, and, therefore, does not include all of the types of the study area. For these reasons, Daubenmire's vegetation types were not used in this study, and a Gleasonian approach to framing the units of the Idaho Selkirks was used (Matthews 1996). The types here are not based on their climax presentation, and for that reason are dynamic within their amplitude of species assemblage, elevational range, and cover.
Using the frameworks from U.S. National Vegetation Class Standards (USNVC 2017), alongside the U.S. Geological Survey, Northwest Gap Analysis Program Project (USGS/GAP 2011) and NatureServe (2020), this study outlines previously recognized larger vegetation classes and the types within, and for more diverse vegetation types, include subgroups within ALISO Faust, Legler, and Tank  them. Using this foundation, this study was able to describe recurring vegetation types primarily using observations made during the study.
The five main classes used include: 1. Forest, 2. Grassland/Shrubland, 3. Wetland/Riparian, 4. Open Rocky, and 5. Anthropogenic. These classes are dominant within the Northern Rocky Mountains, Columbia Basin, and Coastal floristic assemblages described within the USGS/GAP Project (USGS/GAP 2011). Within each class, vegetation types are outlined based on field observations and collections, as well as historical collections and previous studies of the area. Some vegetation types are poorly delimited, e.g., Anthropogenic, but were included due to their distinctive species make-up or large amount of cover within the study area. Selected taxa of the Idaho Selkirks are shown in Fig. 16-24.
1. Forest and Woodland.-This class covers the majority of the study area, with the widest elevation range, from valley floor to just below the crest. All of the types included in this class have a dominance of tree cover on the landscape, with 15% or more tree canopy, as well as containing trees at heights of 5 m or taller.

Montane
Forest.-Montane foothill forests are common throughout the mountain range, ranging from the valley floor at ∼2000 to 5500 ft (610 to 1680 m), on south-and southeast-facing slopes. This type is composed of rocky, dry soil with a dominant canopy and significant forb and shrub understory. The canopy is dominated by Pinus ponderosa at lower, drier sites, and Pinus contorta var. latifolia at higher elevations with colder average temperatures. At the lower end of the elevation range, these areas are often intermixed with Pseudotsuga menziesii var. glauca and Abies grandis. The tree canopy often irregularly covers the landscape with openings into shrub and graminoid communities. Dominant shrubs include Physocarpus malvaceus, Holodiscus discolor, and Rosa gymnocarpa at lower elevations, and as elevation increases forbs, subshrubs, and graminoids replace the larger shrubs. Pseudoroegneria spicata, Festuca rubra, and Poa stenantha are the common grasses, with Carex geyeri and Carex rossii often in shady areas within this vegetation type. Although generally dry, these areas are briefly moist in the spring, with an assemblage of early-blooming forbs including Balsamorhiza sagittata, Lomatium multifidum, and Castilleja hispida var. hispida.
This forest type, while prevalent, does not cover extensive areas within the range, as it is associated with disturbance from fire, logging and recreation. With this disturbance dynamic, these forests can transition into Montane Grassland/Shrubland, if the canopy becomes less dominant. This type is found in Columbia Basin floristic influenced areas, located on the southern and eastern side of the Idaho Selkirks, presumably due to the rain shadow effect, including southwestern slopes above Priest Lake. Notable areas within the Idaho Selkirks are Parker Trail, Long Canyon, Caribou Creek, and Baldy Mountain Road (Fig. 3).

Mesic Forest.-Northern
Idaho is famous for its old growth western red cedar (Thuja plicata) stands, disjunct from their predominantly coastal distribution (Brunsfeld et al. 2000). This forest type generally occurs on flat to gently sloping terrain of valley floors and lakesides at elevations of 2000-3500 ft (610-1070 m).
The Mesic Forest type is dominated by a canopy of Thuja plicata and Tsuga heterophylla. Depending on topography and disturbance regimes, different forest floor vegetation is present. In areas with underground seeps, flow-through creeks or river terraces, as seen in Upper Priest Lake vicinity, the forest floor is often covered in an assemblage of ferns. The most common ferns present are Athryium filix-femina and Dryopteris expansa; however, Polystichum munitum, Polystichum andersonii, Dryopteris filix-mas, Equisetum sylvaticum (Fig. 17), and Botrypus virginianus are also prevalent. Within creekside or seep sites amidst the woods, Oplopanax horridus and Asarum caudatum can also occur (Brunsfeld et al. 2000). However, this forest type is dynamic, and can also be loosely vegetated, with the forest floor carpeted exclusively in duff, often with Corallorhiza mertensiana or Pterospora andromedea earlier in the season, and by mid-July often contain several Botrychium Sw. species. Earlyflowering forest floor forbs include Viola glabella and Tiarella trifoliata var. unifoliata, along with scattered Vaccinium ovalifolium and Gaultheria ovatifolia. This vegetation type is variable based on logging and disturbance, and is most diverse in its old growth forms. This type is common adjacent to Priest Lake, in the vicinity of Upper Priest Lake, and along the Priest River corridor from Upper Priest Lake as far north as American Falls.

Subtype 1.25 Old Growth Mesic Disjunct Forest.-The Idaho
Selkirks are well known for having the longest continuous old growth stands of Thuja plicata (Fig. 5;McGrath et al. 2002). These areas contain all the other characteristics of the lower mesic disjunct forest type; however, they lie in basin, valley, or terrace-type plateaus. This topography can trap and isolate regional weather patterns, allowing for weather to settle longer, resulting in a slightly warmer microclimate. Additionally, this subtype occurs in areas with low natural and anthropogenic disturbance, and therefore old growth stands are scarce, often found amidst larger stands of Mesic Forest. Rare Idaho species such as Polystichum braunii, Streptopus streptopoides, Sanicula marilandica, and Tellima grandiflora are present in these warmer northern sites within the study area, often accompanied by Taxus brevifolia (Fig. 20). Notable sites are the Upper Priest Lake RNA, Smith Creek, West Fork Cabin, and American Falls. This subtype often represents around 5% or less cover of the study area; however, it contains species found nowhere else within the state.

Mid-Elevation Conifer
Forest.-One of the most widespread and homogenous vegetation types in the Idaho Selkirks is that of the Mid-Elevation Conifer Forest, dominated by canopy of Picea engelmannii. At lower elevations, Picea engelmannii is joined by Larix occidentalis, Abies grandis, and Pinus monticola, and as elevation increases, by Abies lasiocarpa, which becomes dominant at higher elevations. The canopy, while usually thick, often contains openings, both natural and from anthropogenic disturbance. These openings are dominated by a thick shrub layer of Rhododendron menziesii, Rhododendron albiflorum, and Vaccinium membranaceum. Within moist seeps there can be orchids such as Neottia banksiana and Corallorhiza maculata, as well as common forbs such as Maianthemum stellatum, Clintonia uniflora, and Trillium ovatum var. ovatum. Openings into drier and rockier areas within the forest are often comprised of common forbs such as Pedicularis bracteosa, Antennaria microphylla, Sedum lanceolatum, and Montia parviflora.
The Mid-Elevation Conifer Forest type ranges from ∼3700 to 5500 ft (1070-1740 m), mostly on northern aspects, but exists throughout its elevational band in various aspects and topographies, although it is often found on dramatically steep slopes and ridges. It converges with various vegetation types including talus slopes, rocky summits, and moist meadows within the study area. This type is ubiquitous within the Idaho Selkirks on all sides of the range, and is easily seen in nearly any approach of the crest. Notable areas are Smith Ridge, Russell Ridge, Trout Creek, and Mollies Lake.

Subalpine Conifer
Forest.-Throughout the mountain range the Picea engelmannii-dominated middle-elevation conifer forest transitions into both rocky openings and Subalpine Conifer Forest. This type occurs between ∼5500-7000 ft (1670-2130 m), usually with a short flowering season. This area can either be exclusively dominated by Abies lasiocarpa or Pinus albicaulis, or intermixed, often with Pinus contorta var. latifolia on the lower end of the elevation spectrum. These areas are often sparsely vegetated, rocky, and dry.
When this type is dominated by Abies lasiocarpa, the common associated species are Luzula hitchcockii and Hieracium triste. When open and rocky, the dominant tree is Pinus albicaulis, associated with Arnica ovata, Penstemon ellipticus, and Danthonia intermedia. These areas can also be associated with dominant heath ground covers, such as Cassiope mertensiana and Phyllodoce empetriformis on northern aspects and on summits. This area is broadly distributed on all sides of the Selkirk crest.
2. Grassland/Shrubland.-This class is one of the least common in the Idaho Selkirks, with surprising levels of diversity, and produces multiple species range extensions. The types organized here are all characterized by 10% or less tree canopy. The following vegetation types are often associated with intermediate stages of ecological succession, often referred to as a seral stage following disturbance (Barbour and Billings 2000). Disturbance from fire or anthropogenic causes can lead to such openings, not dominated by tree canopy, and subsequent natural disturbances from wind events or rain and snow can maintain these vegetation types.
2.1 Montane Grassland/Shrubland.-The Columbia Basininfluenced Montane Grassland/Shrubland type exists abundantly throughout northern Idaho; however, in the moist and boreally influenced Idaho Selkirks, this type resides predominantly on the eastern side of the range. Beginning on the edge of the valley floor at low elevations of ∼2500 ft (760 m), and continuing through lower-mid elevations of ∼4500 ft (1370 m), this type is restricted to south-and southeast-facing aspects, on both softer and dramatic slopes. The slope and aspect promote heavy and early drainage of snow melt and rain, which likely contributes to this type's early phenology, with peak flowering times as early as mid-April. While these areas tend to be mostly open, they often lie within the Montane Forest vegetation type.
The majority of montane grasslands in the Idaho Selkirks are dominated by an assemblage of grass species with significant, yet often scattered, shrub cover. Shrubs often consist of an assemblage of Physocarpus malvaceus, Holodiscus discolor, Prunus  aspect, open exposure, and distribution in the eastern and southern range of the study area, this area has early and brief spring phenology, before it is quickly dried up. The typical assemblage within the seeps includes Hemieva ranunculifolia, Aphyllon purpureum, and Erythranthe microphylla, often joined by a mix of other early flowering montane forb species.

Bear Grass
Meadow.-In the Selkirk Range of northern Idaho, Xerophyllum tenax carpets expansive openings, creating its own meadow, often following natural or anthropogenic disturbance. These meadows are exclusively at middle to high elevations, between ∼5000-6500 ft (1524-1980 m), typically on dry, south-facing slopes or ridgelines, and often bordered by Mid-Elevation and Subalpine Conifer Forest types. Often, rocky outcrops and/or Abies lasiocarpa or Abies grandis groves are interspersed, but the majority of the meadow is dominated by Xerophyllum tenax, with significant bare ground. Common forbs within the area include Hieracium scouleri, Erythronium grandiflorum, and Eremogone capillaris var. americana, along with the graminoids Festuca occidentalis and Carex geyeri. Within the study area, Ionactis stenomeres is only found in or adjacent to Bear Grass Meadows. This vegetation type is found on both sides of the mountain range from the Priest Lake area south. Notable sites include Camels Prairie and Mount Baldy.
3. Wetland/Riparian.-Some of the most notable habitats found in the Selkirk Mountains of Idaho lie within its wetland systems, despite their relatively small cover of the study area. Special attention is spent on these vegetation types, as they contain more than 10% of the State's rare flora (Lichthardt 2004). The following vegetation types are based on observations made during this study and are different than the vegetation types noted in the Conservation Strategy for Panhandle Peatlands (Bursik and Moseley 1995), as they are not all present fully in the Idaho Selkirks. While all of the wetland types listed are variable, two things remain constant between them all, including the presence of moisture year-round, and that they lie in generally flat topography, regardless of elevation.

Ombrotrophic Bog.-Ombrotrophic
Bog is used here to refer to an area that gets the majority of its moisture and nutrients directly from precipitation and snow, rather than from water features such as streams, springs, or groundwater (Chadde et al. 2011). This delineation separates it as a "true" bog, versus a fen, and is the only type of true bog in Idaho. The water table in these areas changes drastically throughout the season, and with these sites often being waterlogged, flowering time is often early to late summer (Lichthardt 2004). These areas are characterized by a raised layer of moss, predominantly Sphagnum L. spp., that typically covers past organic matter, such as downed logs, which together thickly carpet the area, and assist in moisture retention for these areas.
This type is rare throughout the study area, occupying only a few hectares, and transitioning into other wetland systems. The Ombrotrophic Bog vegetation type is distinctive in both its notable assemblage of rare plants, as well as its distinctive site features. These sites are found at lower elevations of ∼2000-3000 ft (610-910 m), and are all either adjacent to, or north of Priest Lake, which is hypothesized here as a product of the glacial activity and high mineral and sediment deposition in these areas (Lichthardt 2004). Additionally, many of these areas are hidden within the larger landscape, often in pockets or basins.
Two inconspicuous matting species, Vaccinium oxycoccos (Fig. 21) and Gaultheria hispidula, occur in this vegetation type. Additionally, Scheuchzeria palustris, Lysimachia europaea, Carex chordorrhiza, Utricularia ochroleuca, and Andromeda polifolia occur in this system. Other species found here are Drosera rotundifolia, Eriophorum chamissonis, Carex magellanica subsp. irrigua, and Dryopteris cristata. These sites are often comprised of a sparse canopy of trees and/or a weak shrub system, or are devoid of trees or shrubs. Just as likely in this type is an abundance of downed and dead trees from past changes in the water table. Notable areas with some type of Ombrotrophic Bog in the Idaho Selkirks are in Bear Creek Basin, the Priest Lake Thoroughfare, Chase Lake, and Mosquito Bay, all located on the western and northern reaches of the Idaho Selkirks.
Subtype 3.15 Paludified Forest.-The Paludified Forest is often composed of a concentration of downed logs with a thick canopy of trees, resulting from erosion and water table changes that accompanies a high soil organic layer and accumulation of peat. This type is often a mix of Pinus contorta, Pinus monticola, Abies lasiocarpa, Abies grandis, Picea engelmannii, Thuja plicata, and Tsuga heterophylla, with an assemblage of mesic forest and deciduous riparian forbs underneath. The Paludified Forest is not common, but one example of this type is Bear Creek Basin, where the only documented population of Maianthemum dilatatum in the State of Idaho occurs (Fig. 18).
Subtype 3.16 Floating Mat.-Floating Mats are microsites within Ombrotrophic Bogs and flow-through fens. They consist of dense mats of Sphagnum spp. that lie on top of water or mud adjacent to a bog or water feature, and physically are unattached to what lies underneath. Like the Paludified Forest, Floating Mats only exist in lower elevations; however, they are composed completely of Sphagnum spp. and host notable species such as Vaccinium oxycoccos. Floating Mats have been observed at Chase Lake, Lee Lake, and Bear Creek Basin.

Flow-Through
Fen.-Flow-through Fens, also referred to as peatlands, are wetlands that have some amount of Sphagnum spp. cover, from patchy to dominant; however, vascular plants cover the majority of the landscape, even if there is a Sphagnum spp. layer underneath. Peatlands exist between low valley floor or lakeside elevations at ∼2400 ft (731 m) to middle elevations at ∼4500 ft (1370 m), and are characterized as distinct from bogs in receiving nutrients through groundwater, as well as precipitation (Lichthardt 2004). Often, they occur in old river oxbows, river terraces, old lakebeds, creekside, or adjacent to drainages, and are flat or with only a slight slope. Lower-elevation sites are often lakeside, and tend to be more open; examples of this are Chase Lake, Lee Lake, and Bog Creek. Higher-elevation sites are often creekside, and tend to occupy valley floors. Examples of this type are Cow Creek, Westfork/Smith Creek, Grass Creek, and Trapper Peak wetlands, all bordered by mixed conifer forest.
In fens with higher sphagnum cover, diverse assemblages of species are present, many of which are listed sensitive species. Notable sedges and forbs include Carex magellanica subsp. irrigua, Trichophorum alpinum (Fig. 22) Salix sitchensis, and Salix bebbiana. Herb and graminoid cover can loosely persist beneath the shrub cover; however, the shrub cover can be dense and difficult to physically move through.

Sedge
Wetlands.-Occurring from ∼2000-3500 ft (610-1070 m), are sedge-dominated wetlands that are groundwater or spring dependent (Fig. 6). Sedge Wetlands are often on the edge of disturbed water features, often covered in Sphagnum spp., but never dominated by it. The most common cover here is a mix of sedges and rushes, but often a dominant sedge such as Dulichium arundinaceum or Carex cusickii may persist throughout the whole wetland complex with pockets of other sedge species intermixed. Typha latifolia is also common in these areas and can create large stands. Common forbs include Lycopus uniflorus, Erythranthe moschata, Cardamine pensylvanica, and multiple Sparganium spp., found emergently and/or aquatically. This type occurs in the mid-to southern portion of the mountains where less glacial activity and higher disturbance from logging and development has occurred. Notable areas of this type are Riley Creek, Thornby Lake, and Blue Lake. While all the other riparian vegetation types occur predominantly on flat topography, the Deciduous Riparian is likely found on slopes as well. This type is observed throughout the range, but was most common on State Land both east and south of Priest Lake.

Subalpine Wet
Meadow.-While other wetland/aquatic vegetation types within the study area occur generally at lower elevations, the most distinguishing feature for the Subalpine Wet Meadow is its higher elevation, ∼5500-7000 ft (1680-2130 m). The Subalpine Wet Meadow can be highly variable, but is distinguished by flat topography, flow-through riparian systems, and location adjacent to slopes or lakes. This type often serves as a drainage area, and therefore contains high organic material. While these areas are distinct, they do not contain the same levels of floristic rarity as the lower elevation wetland systems. They are almost always open, carpeted in varying types of peat moss, and often have stunted Picea engelmannii or Abies lasiocarpa. Heath dominance is a characteristic of this vegetation type, frequently composed of a mix of Cassiope mertensiana, Kalmia microphylla, and Phyllodoce empetriformis, though Kalmia microphylla is often dominant. Leptarrhena pyrolifolia and Eriophorum angustifolium subsp. angustifolium are almost always present in this type, with a mix of forbs and graminoids, including Viola palustris, Pedicularis groenlandica, Potentilla drummondii, and Carex kelloggii. Two clubmosses also occur in this environment, Diphasiastrum sitchense, locally common in the Idaho Selkirks but listed as rare in the State, as well as the newly listed, sensitive and locally rare Diphasiastrum alpinum, which are easily overlooked Vascular Flora of the Selkirk Mountains, Idaho as they hide within mats of Cassiope mertensiana. Subalpine Wet Meadows are found throughout the range in their elevation band; notable sites are found adjacent to Beehive Lakes, Hunt Lake, Lions Head, and Pyramid Peak.
3.6 Aquatic.-Aquatic, while a general term, here refers to open bodies of waters. These areas contain water that is present all year long, and in the study area consist of lakes and ponds. Submerged and emergent aquatic species that are prevalent consist of Nuphar polysepala, Elodea nuttallii, Utricularia vulgaris, and multiple species of Potamogeton L. The edges of low-elevation aquatic zones are often home to uncommon species, such as Cicuta bulbifera and Artemisia ludoviciana. Isoetes bolanderi and Callitriche heterophylla frequent higherelevation lakes throughout the mountain range, and the edges of these higher-elevation lakes often grade into small mesic meadow sites, predominantly bordered by sedge species. Notable aquatic sites are the Priest Lake Thoroughfare, Chase Lake, Blue Lake, and Hornby Lake, all of which are at lower elevations.

Open
Rock.-While there are many types of rocky outcroppings, they are predominantly microsites within other sites and too variable to define at the same degree as the other vegetation classes. However, the types described here are included within this class for their shared characteristic of sparse vegetation. The USNVC System refers to rocky areas as an extreme form of a shrubland, defined by a lack of tree canopy, as well as nonvascular species dominance (USNVC 2017). The sparse vegetation is attributed to the lack of soil in these habitats, as large stable areas are often not present in rocky areas. The dominance of mosses and lichens is common in open rocky areas, and due to the emphasis of this study on vascular plant species, these were not focused on, but are noted as a contributing factor of this class.

Granite
Crest.-The Idaho Selkirks are well known for the dramatic and rugged granite crest that divides the mountain range into its eastern and western portions. On the rock faces themselves, there are often few to no species growing, but within the crevices are either wet areas or dry weathered areas. The crest itself begins at ∼7200 ft (2190 m) and goes to ∼7600 ft (2310 m). These peaks are under snow for the majority of the year, and depending on aspect, elevation, and rock formation, contain sporadic patches of soil with vascular plants amidst rock faces and outcroppings. In wetter areas it is typical to find Rhodiola integrifolia subsp. integrifolia, Saxifraga hyperborea, and Solidago multiradiata in the cracks of otherwise bare rock. In drier areas Boechera lyallii, Piptatheropsis exigua, and dwarf forms of Juniperus communis var. kelleyi occur. Some notable forbs found within sparse patches of soil amidst rocky outcrops on the crest are Dryas hookeriana, Lloydia serotina, Tonestus lyalli, and Luetkea pectinata. There has been some disagreement in the past whether the Idaho Selkirks contains a true alpine assemblage. While pockets of granitic crest can host alpine species that persist through major weathering, this study treats this area as the highest-elevation portion of subalpine in the study area, and therefore not true alpine. Notable crest areas with both dry and wet crest zones are Twin Peaks, Mt. Roothaan, and Lions Head. Subtype 4.15 Fell Field.-Lying just below large dramatic granite faces are thin strips of vegetation often referred to as subalpine Fell Fields. These areas often have poorly developed rocky soils and can have snow persisting until August. It is quite typical to find Ranunculus eschscholtzii, Gaultheria humifusa, Juncus parryi, and Carex phaeocephala within these fields. However, northeast faces below the crest where weather settles often boast verdant displays of common and uncommon forbs, found flowering briefly in late July through mid-August. One notable species found here is Ivesia tweedyi, found on the northeast face of Chimney Rock, a notable fell field found in the study area. Other notable fell fields found within the crest system are below Myrtle Peak, Lions Head, Twin Peaks, and Smith Peak.
4.2 Talus.-Lying within steep slopes at middle-, ∼4000 ft (1220 m), to higher, ∼7000 ft (2130 m), elevations are granite talus slopes, sometimes referred to as scree, consisting of granite rubble and covering a notable amount of the range. Some talus slopes are prior avalanche chutes, characteristic features of the defined Selkirk ecoregion (McGrath et al. 2002). While they are sparsely vegetated, they have a distinct pattern of species amidst their thin soil patches, pocketed within the large granite boulders. Often mid-elevation conifers can make islands within the large swaths of talus. Throughout the Idaho Selkirks, talus slopes occur on all sides of the crest, but do not appear in low elevations. Rubus idaeus subsp. strigosus, Arnica ovata, and Luzula parviflora are three common species found within talus areas. This is mostly a transitional type between Subalpine Conifer Forests, Subalpine Wet Meadows, and The Selkirk Crest.

Mid-High-Elevation Rocky
Outcrop.-Similar to the other rocky types in the area, sparse to low vegetation characterizes the Mid-High-Elevation Rocky Outcrop, sitting between ∼5500-7500 ft (1680-2290 m). This type can be found within other types at similar elevations, appearing as a rocky outcrop that is often south or southeast facing, often with downhill slopes. The rocky outcrop, also referred to as a bald, can also consist of a coarse rocky summit, typical for lower peaks or peaks on the eastern side of the range. This type is often dry, with small patches of soil development, and variable aspect, especially in its summit form. Common species on the lower end of the elevational range are Lomatium sandbergii, Heuchera cylindrica, and Hypericum scouleri. At higher elevations common species are Saxifraga austromontana, Antennaria media, Phyllodoce glanduliflora, and Festuca saximontana var. purpusiana. These areas typically have low to no shrub or tree cover, except for occasional Juniperus communis var. kelleyi, often windswept and heavily weathered. On the other end of this type's spectrum are moist rocky outcrops, occupied by high-elevation seeps. Wet high-elevation rocky outcrops often exhibit an assemblage of fern species, such as Athryium distentifolium and Polystichum lonchitis, often accompanied by Arnica gracilis. Both dry and seepy outcrops are typically marginal habitats, but ubiquitous as one leaves the Mid-Elevation Conifer Forest and heads higher in elevation. Notable areas with this vegetation type are peaks like Parker Peak, Horton Peak and Myrtle Peak.

5.
Anthropogenic.-Anthropogenic-influenced areas cover a large portion of the study area. It is difficult to cleanly identify structure and patterns for these disturbed landscapes. Growth forms and dominant canopy can vary; however, abundant weedy annual forbs or graminoids are indicative of this class. Uncommon spacing and shapes are often left behind from disturbance, making it difficult to delineate distinct reoccurring patterns on the landscape, both physically and temporally. This class is considered by many to be a seral type of a former stage; however, based on the uncertainty of former stage regeneration, they are included here as anthropogenic types.

Harvested
Forests.-This vegetation type is one of the most dominant vegetation types in the study area, specifically in the Idaho State Endowment Lands, but also present within Forest Service and private industry land holdings. This type has been referred to as "bulky" in the USNVC standards for its high variability, and for lacking reproducible units of description (US-NVC 2017). Harvested forests were observed between elevations of ∼2000-5500 ft (610-1680 m), on nearly all type of land ownership, from state, to public, to private industry. While there is a history of multiple types of logging, two main types of harvested forest were observed.
The first type of timber harvest observed is ground mechanized harvest, which directly impacts the soil with machinery. The ground mechanized harvest was often observed on harsher, drier sites where Ceanothus velutinus readily colonizes following ground mechanized timber harvest. The second type of timber harvest observed harvests timber from the skyline using suspended cables and therefore has a lower soil impact. Skyline type harvest was observed generally in sites with milder, moister conditions, and post-harvest colonizer species were generally Holodiscus discolor, Ceanothus sanguineus, and Acer glabrum var. douglasii. However, it was common to see more recently harvested forests with sparse to no vegetation, with either wellspaced trees left behind, stumps, or large piles of slash. This vegetation type is often a strip of disturbed ground next to a large area of disturbance, such as a clear cut or a gravel pit, and is found adjacent to every vegetation type within the study area except for all Open Rocky types and the Ombrotrophic Bog. There are two main types of roadsides observed within the study area-dry and rocky gravel roadsides and moss-carpeted roadsides. The gravel roadside is the most prevalent of the two, and the highest density of weeds and introduced species are found in this type, typically including Centaurea diffusa, Tanacetum vulgare, as well as invasive grasses such as Ventenata dubia, Dactylis glomerata, and Agrostis capillaris.
The moss-carpeted roadbed is often found adjacent to disturbed mixed conifer forests, often dominated by Thuja plicata, and is carpeted in moss with a wide spectrum of forbs; one noteworthy association is Antennaria Gaertn. spp. and Fragaria L. spp., both indicators for the presence of Botrychium Sw. spp. (Fig. 16;Farrar 2011). This type of specific roadside only exists in the northern section of the mountain range, from low to middle elevations, and is always flat or with a slight slope. This type All roadsides visited were observed from the lowest elevation, ∼1530 ft (740 m) to generally mid elevations at ∼5500 (1680 m). However, there are a handful of roads on the west side of the range that end at the top of ridges or peaks lower than ∼6500 ft (1980 m). Despite a handful of roadless areas within the range, roads exist, whether maintained or not, throughout the entirety of the study area, except for the vicinity of the crest.

Multiple Use.-This mountain range is quite diverse in its
anthropogenic impact over the last century. The study area and its immediate surroundings include agricultural fields, wildlife refuges, historical mines, an experimental silvicultural forest, private property, and even a ski resort. While all of these multiple-use regions are distinct from one another, they all showcase large-scale disturbance on the landscape, patchworked into the mountain range. All areas lack an organic structure and exist from low to high elevations throughout the entirety of the Idaho Selkirks, except for the crest. While they lack reproducible units to delineate them, multiple use areas are prevalent enough within the study area to identify here, and include notable areas such as Priest River Experimental Forest, Priest Lake State Park Campgrounds, Schweitzer Mountain Resort, and Continental Mine.

Fieldwork Summary
Fieldwork in 2019 was focused on covering large portions of the study area that had never been collected, while fieldwork in 2020 focused on filling the prior year's holes, with special attention to taxon-specific collecting. Focused efforts in 2020 were spent on targeting coastal disjuncts, rare species, and taxa not previously collected in Idaho, but expected based on ecology and nearby existing collections (e.g., adjacent Washington State). During the 2019 field season, 49 days were spent in the field and 2090 specimens were collected, and during the 2020 field season, 59 days were spent in the field and 2065 specimens were collected, totaling 108 field days and 4155 specimens. This represents 4.6 collections per square mile. These were collected over 665 collection sites, covering all major physiographic features, elevations, and vegetation types; between one and 55 collections were made at each site (Table 2, Fig. 25).

Taxa of Conservation Concern
Sixty-two taxa of conservation concern are known from the study site, 48 were found during the study, and 14 are based Vascular Flora of the Selkirk Mountains, Idaho on historical specimen records (Table 3). These taxa have been designated as rare through the North Idaho Rare Plant Working Group, one of two working groups based out of the Idaho Native Plant Society (INPS 2022) that evaluates and lists species of conservation concern in the State of Idaho. The rare plant working groups in Idaho use an established system through NatureServe that ranks species based on a multitude of factors including known occurrences, habitat quality/size, and habitat/population threats (NatureServe 2020). Each NatureServe rank is made up of two elements, the state rank (S) and global rank (G). The values of each state and global rank range from 1 to 5, where 1) Critically Imperiled, 2) Imperiled, 3) Vul- ALISO Faust, Legler, and Tank   Table 3. All sensitive taxa found in the study region. Faust versus Historical collections (Hx) aims to display which species were not relocated during the study, and some of the taxa collected by Faust during the study had also been collected prior. Data from Idaho Native Plant Society (INPS 2022 Viola selkirkii G5 S1 Historical nerable, 4) Apparently Secure, and 5) Secure (NatureServe 2020). Of the 62 listed species found in the study area, 20 are state listed as Critically Imperiled, eight of which are only found in the study area within Idaho (Table 3; IDFG 2018). However, 24 species are listed as Imperiled, which speaks to the high concentration of rare and threatened species in the study area, totaling around 8% of the flora. Despite this abundance of sensitive species in the area, this table is not a complete representation of all the species worth listing. Five rare species never before collected in the State of Idaho were picked up during this study and proposed for designation (Faust and Legler 2021). To date nine species were state ranked as a result of this project (Diphasiastrum alpinum, Utricularia ochroleuca and Potentilla drummondii in 2020); Botrychium hesperium, Elymus hirsutus, Cryptogramma stelleri, Eleocharis mamillata, Elymus hirsutus and Ozomelis trifida in 2022). The process for species designation with NatureServe is a collaborate inter-agency effort that is constantly in flux, as increased documentation of flora illuminates the true sensitivity and concern of species.
Of the designated species, the majority are concentrated into the peatland communities. The nutrient content, glacial history, and climate create specialized substrate and topography for these species to inhabit. Despite the high number of rare species, there are still active risks and threats to the populations. Rare species are ranked as such due to restricted ranges, small numbers, and their high susceptibility to environmental changes. While ongoing monitoring of previously listed state species occurs on forest service land, further monitoring will be necessary to incorporate the additional populations discovered during this project.

Non-Native and Noxious Species
Introduced taxa serve as an additional threat to taxa of conservation concern, and with a rise in recreation in the area, there is increased potential threat of greater introduction. Noxious and many aggressive introduced taxa can be fierce competitors on the landscape, often displacing native taxa through advantageous characteristics such as drought resistance, germination timing, seed dispersal, and environmental plasticity (ISPI 2020). In this study, 110 introduced taxa were identified, ten of which are State-listed noxious species (Table 4). The two most prevalent families are Asteraceae Bercht. & J. Presl, which represents 17 of the introduced taxa, and Poaceae Barnhart, which repre-sents 31 of the introduced taxa. The ten noxious taxa were prevalent throughout the range; however, they were generally concentrated to roadsides, multiple use areas, and timber-harvested forests. While montane forests and montane grasslands also contain concentrations of introduced taxa, these non-native species were overwhelmingly found in the anthropogenic vegetation class within the study area. One non-native species was picked up during this study never before collected in Idaho, Euphrasia nemorosa (Faust and Legler 2021). With the majority of the introduced taxa being under-documented, this could be partially attributed to the lack of inventory in the area, or the result of relatively recent introductions to the area.

Value of Survey
Floristic inventories serve as one of the most critical foundations of our understanding of plant diversity, and herbarium specimens are the physical foundation for the study of such diversity (e.g., a species' range, distribution, and systematic treatment; Wohlgemuth 1998). These data are instrumental in assessing shifts in community composition and/or species phenology in an era of massive global change (Willis et al. 2008). It is therefore fundamental for every defined floristic region to have an organized and communicable understanding of its diversity, especially in the face of global change (Ertter and Moseley 1992). This checklist targets government land managers, researchers, and lay botanists interested in exploring the area, and serves as the baseline dataset of the vascular plant diversity for the study area, which will assist in assessment of change over time. Much was unknown of the study area prior to 2019, so this study also serves to fill a gap in our knowledge, not just for the Selkirk range, but for the Idaho Panhandle, as well as the whole state of Idaho and the Pacific Northwest. On top of these impacts, the plant collections, and the silica gel-dried tissue collections associated with them, are a valuable dataset. For example, spatial phylogenetics, a scientific field exploring diversity and landscape change, can take this dataset further to analyze the phylogenetic relationships among the present species (Mishler et al. 2020), and address longstanding evolutionary and ecological hypotheses (e.g., Darwin's Naturalization Conundrum: Marx et al. 2016;Park et al. 2020). Lastly, this inventory serves as a model for studies that integrate historical herbarium specimens into updated floristic inventories.

Thoroughness of Survey
The number of state and county collection records and range extensions documented in the study area illuminate the undercollected nature of the Idaho Panhandle prior to this study. Before the study, ∼2800 specimens represented the 886 square mile study area, which corresponds to a coverage of ∼3.16 collections per square mile. During 2019 and 2020, 4155 collections were made, which accounts for an additional 4.6 collections per square mile. Now the region boasts ∼7.8 collections per square mile, coverage that was doubled during the study. Although these results suggest a thorough collection effort, a flora is never fully collected (Rosenzweig et al. 2003).
There are multiple factors that contribute to incomplete documentation of a flora, including collector bias, presence of relictual species, climate change, increase in anthropogenic influences, and conditions present during a study. Accounting for collector bias is difficult to quantify in this study; however, it is important to note. There is a well-known bias for botanical collecting in close proximity to roads (Daru et al. 2018). This was identified in the initial stages of the study as a known limitation, and efforts to collect remote and difficult-to-access areas were made by multiple backpacking, bushwhacking, peak scrambles, and canoe approaches. However, in looking at the map of collection localities (Fig. 25), there are still many areas that could be accessed with further effort, as well as those that would be too difficult to reasonably access. Another known sampling bias is that of the collector's unconscious preference of site selection and which species to collect. This is demonstrated by the difference in collections between sample years, where many species that were presumably present in 2019 were not collected until 2020. This intersects with the role of specific habitat requirements of particular species and weather conditions observed in a two-year study. This study's two-year window could not capture climate change effects on presence/absence of species in the study area; however, this is a possible contributing factor to species observed, and an area for further study. On top of these factors, this mountain range is constantly changing through the steady addition of introduced species and associated loss of habitat due to anthropogenic activity, both of which occur on a temporal scale for any floristic region, and so updated surveys are vital to the understanding of any region.
Despite these caveats, this survey serves as the most comprehensive snapshot of the vascular plant diversity of the Selkirk range in Idaho, and includes historical specimen data that combine the efforts of botanists collecting in the region for the past century with collections made as a part of this study. Some specific habitats, such as montane grasslands, were gravely overlooked before this study, as exemplified by range extensions and county records of species otherwise common to this habitat outside of the study area. Multiple widespread montane grassland species had never before been collected in the study area (e.g., Idahoa scapigera, Athysanus pusillus, Ranunculus glaberrimus) and several boreal species new to the Idaho Panhandle were also located (e.g., Diphasiastrum alpinum, Elymus hirsutus). Nevertheless, there is a need for continued surveys of the Selkirk crest, areas of proposed development, and heavily trafficked areas, as these areas pose the greatest threat for the loss of species diversity, and the introduction of non-native taxa.
Expected finds.-This survey did not recover every species historically occurring in the study region. A part of this was intentional in not targeting well collected areas, such as Priest River Experimental Forest. There is a nursery located there and uncommon weeds have historically been found there, e.g., Chenopodium album, Atriplex patula, and Hordeum jubatum subsp. jubatum. Additionally, eight historical additions are known from individual roadside collections. Lastly, Robert Bursik's specialization in fen systems of the inland northwest as well as his unmounted backlog contributed seven additional sedges from fen systems within the area that this survey overlooked. Utilizing these historical collections contributes to a more comprehensive floristic treatment and this survey is indebted to the Idaho botanists that came before.

Taxonomic Discussion
When summarizing a regional flora, not all individuals fit neatly into a species circumscription. The study area lies at the intersection of multiple floristic regions, where the opportunity for species to overlap in distribution and intergrade is high. For example, there are multiple instances where overlapping populations of typically disjunct coastal and inland taxa result in plants with intermediate morphologies. It is unclear if this repeated pattern is the result of hybridization between truly distinct coastal and inland taxa, or the result of phenotypic plasticity-another avenue for further study.
Below, species circumscriptions are treated as hypotheses, and the evidence from this study is provided to encourage further investigation into several taxonomic grey areas identified in the following groups (Ertter 1997).
Arnica L. subgenus Chamissonis Maguire.-Arnica (Asteraceae) is known for its taxonomic complexity (Gruezo 1994). Of the six Arnica species in the study area, A. ovata and A. mollis were treated as part of subgenus Chamissonis by Gruezo and Denford (1994). Both species are found commonly in the study area, and just as common were intermediate forms between the two. Treatments in FNA, FPNW and the Illustrated Flora of British Columbia were inconsistent, specifically with respect to weighting variability in pappus color and structure between these two species (FNA 1993+;Douglas et al. 1999;Hitchcock and Cronquist 2018). Two studies were used to supplement the current treatments, Gruezo and Denford (1994) on Arnica subgenus Chamissonis, and Straley (1980) on subgenus Austromontana Maguire. Both authors provide a systematic revision for the groups, in which they cite specimens with duplicates housed at ID. The cited specimens were used as the basis for a morphological analysis of all specimens from this study that appeared to be A. ovata or A. mollis from subgenus Chamissonis, as well as A. latifolia from subgenus Austromontana, which is easily confused with the preceding two species. It is also likely that A. mollis and A. ovata lacked clarity in treatments due to their former treatment as synonyms (Gruezo and Denford 1994).
Using Gruezo and Denford's (1994) treatment, the specific characteristics of A. ovata and A. mollis became clearer, based on head shape, pappus color, cauline leaf attachment, cauline leaf shape, and basal leaf shape. After specimens with clear morphologies were verified, the remaining intermediate specimens held a distinct pattern. Intermediate specimens matched the majority of the delimiting factors for A. ovata, yet were morphologically similar to A. latifolia in habit and appearance. These intermediate specimens were annotated to Arnica ovata ?, predominantly due to intermediate pappus color and cauline leaf attachment. Based on this pattern, this study hypothesizes that there are two different forms of A. ovata found in the study area: the distinctly sticky-leaved A. ovata and the potential hybrid A. ovata × A. latifolia, which is likely due to the probable hybrid origin of A. ovata (Ekenäs et al. 2007). This hypothesis needs further investigation, reflected in the lack of clear agreement between treatments on these species circumscriptions.
Rosa gymnocarpa Nutt.-Rosa gymnocarpa (Rosaceae) presents another case of potential intergradation in the study range, highlighting the area's noteworthy overlap of coastal and interior distributions. The most recent treatment for Rosa gymnocarpa (Ertter and Lewis 2016), which was published after the FNA treatment (Lewis et al. 2019), recognizes two subspecies, loosely ascribed to coastal and inland distributions. Rosa gymnocarpa subsp. helleri, recognized recently as the inland subspecies, is more robust with open stem architecture, sparse prickles, and large leaflets, as compared to the coastal subspecies, Rosa gymnocarpa subsp. gymnocarpa (Ertter and Lewis 2016). While there are clear specimens from the study area of R. gymnocarpa subsp. helleri, there were also intermediate forms that displayed characteristics of both subsp. helleri and subsp. gymnocarpa. These intermediate specimens either did not show the extreme forms of open stem architecture, or had varying-size leaflets, or had sparse to dense prickles and were identified simply as R. gymnocarpa. The checklist accordingly includes both R. gymnocarpa and R. gymnocarpa subsp. helleri, to accurately capture the diversity in the area. Rosa gymnocarpa subsp. gymnocarpa may be present in the study area, but typical forms were not represented among the collected specimens. Further targeted collection efforts in the region will be necessary to better understand variability across these subspecies, and the potential of phenotypic plasticity with respect to these defining intraspecific characteristics, especially where taxon ranges potentially overlap.
Other putative hybrids.-In addition to the intermediate forms observed in both Arnica and Rosa, there were also multiple putative hybrids observed in the area. Diphasiastrum alpinum × D. sitchense (Lycopodiaceae) was first documented in the area in 1989 (Bob Moseley 1677, ID). Additional putative hybrids found in the study area include Potentilla drummondii × P. glaucophylla (Rosaceae) and Elymus glaucus × E. hirsutus (Poaceae), both with clear morphological evidence of intermediacy and proximity to populations of the putative parental species. Upon reviewing the majority of Betula pumila and B. glandulosa (Betulaceae) specimens for the State at ID, it seems likely that hybridization between the two species is occurring, based on intermediate characteristics and lack of typical forms of B. pumila. However, further work is needed here before definitively characterizing the probable hybrid nature of these Betula L. populations in the Idaho Selkirks.

Symphyotrichum (Nees) A.G. Jones.-The Symphyotrichum
(Asteraceae) specimens collected in this project exhibit weak species boundaries; specifically, S. foliaceum, S. subspicatum, S. cusickii, S. bracetolatum, and S. spathulatum displayed integrading morphological characteristics. Many of the species are hypothesized allopolyploids or autopolyploids, with origins determined by phylogenetic and morphological analyses (Brouillet et al. 2002;Hitchcock and Cronquist 2018). With no clear agreement on species boundaries, FNA and FPNW present conflicting treatments, pointing to the need for focused studies investigating species boundaries in this clade (FNA 1993+).
Kalmia microphylla (Hook.) A. Heller.-As with Rosa gymnocarpa, Kalmia microphylla (Ericaceae) is divided into coastal and inland varieties (Hitchcock and Cronquist 2018). Historical collections in the study area indicate the presence of both K. microphylla var. microphylla (generally at high elevation) and K. microphylla var. occidentalis (generally at low elevation). The specimens collected during this study represent both clear populations of the inland K. microphylla var. microphylla and intermediate populations that display characteristics of both var. occidentalis (e.g., robust specimens up to 1 m tall) and var. microphylla (e.g., broad, ovate leaves < 2 cm long, and small calyces and corollas). However, none of the historical collections or those specimens collected during this study could be unambiguously identified as the coastal K. microphylla var. occidentalis. In the five-set volume of the FPNW (Hitchcock et al. 1959), it is noted that the type specimen for K. microphylla var. occidentalis was described from a known zone of intergradation for the two varieties. Therefore, proper application of the varieties needs further work. A recent treatment by Meyer et al. (2020) dismisses the varieties on the grounds that their minor morphological differences do not merit taxonomic recognition. Despite uncertainty over the taxonomic status of the varieties of K. microphylla, both varieties are included in the checklist to fully capture the morphological diversity present in the study area.

Threats to the Flora
Landscapes change with time, and there are countless threats that could contribute to loss or changes in species diversity in the study area including climate change, recreation, and timber harvest. This is not a complete account of potential threats to the present biodiversity, which also include development, mining, grazing, and road building, but represents the primary threats.
Climate change.-Climate change is an active threat, even to such a moist and temperate region. The Priest River Experimental Forest recently completed a 100-year climate study of the forest that found a steady rise in average temperature, an increase in snowmelt rates, and an increase in stream runoff, and projected a continuation of this trajectory (Tinkham et al. 2015). The Idaho Selkirks receive the majority of their water from snowmelt, and the timing of snowmelt directly influences the phenology of vascular plants, especially at high elevations within the study area (Winkler et al. 2018).
While species that currently occupy lower elevations can potentially move to higher elevations towards suitable growing conditions, species that are restricted already to the highest elevations bear the greatest risk (Corlett and Westcott 2013). Several species previously collected from subalpine areas on or adjacent to the crest were not rediscovered during this study, including Lewisia triphylla, Luetkea pectinata, Lloydia serotina, Draba incerta, Silene acaulis, and Poa paucispicula. These species could very well still be present and stable in the study area and were potentially overlooked by the study. These species also could have reduced populations or been extirpated from the area due to climate change. Nonetheless, the habitat requirements for these species to reside in abundance may no longer be present in the Idaho Selkirks. That said, several other species also restricted to higher elevations were found during the study, including Dryas hookeriana, Artemsia michauxiana, Cherleria obtusiloba, and Ivesia tweedyi. Further study will be necessary to determine if these species indeed have specialized habitat requirements that are now limited in the Idaho Selkirks. Recent dispersal and dispersal limitations are two additional factors that may explain the limited distribution of localized high-elevation species in the study area. Targeted monitoring on the Selkirk Crest is necessary to continue to document the direct impacts of climate change on the species assemblage of the area.
Anthropogenic threats.-Priest Lake and the mountains surrounding the lake are well known for their summer and winter recreation. This study took place during the onset of a global pandemic  and, as a result, a notable increase in outdoor recreational activity during the 2020 field season was observed. During the 2020 Labor Day weekend alone, 35,000 visitors were counted just at Priest Lake, and in talking with land managers about this increase, recreation was deemed the biggest immediate threat to the area (D. Brown, Idaho Department of Lands, pers. comm. 2020). Known consequences from increased recreation include increased foot traffic, compacted trails, new trails being made, increased disturbance, introduction of weeds, increased spread of weeds, and disturbance of wildlife habitat (D. Brown, pers. comm. 2020). While an increase in recreation could be interpreted as a positive, for this area, the rate of recreation observed during the 2020 field season is unsustainable, and if it were to continue, would impact the health of the landscapes that hold the floristic diversity described here. Recreation has also expanded into physical development on the landscape, which continues to rise.
The history of logging in the area covers a broad span of approaches, ecologies, and stakeholders that has manifested in the continued investment and dedication to using Idaho State Endowment Lands managed by the Idaho Department of Lands (IDL) for economic gain, the very mission of IDL (IDL 2020). Logging is a noted threat to the health of many plant populations in the study area. Plant populations in peatland and wetland complexes have shown sensitivity to water table fluctuations caused by logging in and around these sensitive plant populations (Bursik and Moseley 1995). Any habitat-altering activity poses a threat to populations, and depending on population size, these activities could potentially eliminate small, fragile populations. Fire, drought, and even beaver activity can bring notable change; however, irreversible damage to the hydrology of these landscapes serves as the biggest threat (Bursik and Moseley 1995).
acknowledgements This study occurred as the basis for the first author's master's thesis at the University of Idaho. This project was made possible by multiple avenues of financial support. The Stillinger Expedition Grant provided the bulk of funding for the 108 days of fieldwork in addition to grants from the Torrey Botanical Society, American Society of Plant Taxonomists, and the Palouse Audubon Society. With this assistance this project was able to hire multiple field assistants, Peri Lee Pipkin, Beau Romeo and Whitney "Moose" Griswold. As well, huge thanks to those who joined in the field, Saff Killingsworth, Stella Rose Waxwing, Malia Santos, Megan Ruffley, Jamie Meyer, Jasmyn Hinton, and 2019 Idaho Foray Participants.
This project is grateful for the support from Idaho Panhandle National Forest Botanist Jennifer Costich-Thompson, Tom Weitz at the Priest River Museum, and Kyle Nagy at the Sandpoint Organic Agriculture Center. We are honored that Ana Armstrong, representative for The Kalispel Tribe of Indians, and Pamela Rentz, representative of The Kootenai of Idaho, were willing to share and educate on the indigenous history of the region.
We are grateful for the host herbaria for this project, as well as the Stillinger Herbarium's undergraduate workers, staff, and volunteers. As well, multiple Idaho botanists and members of the Stillinger Herbarium's wide net-Barbara Ertter, Alma Hanson, Derek Antonelli, Karen Grey, Janice Hill, Lynn Kinter, and Michael Mancuso-all provided guidance and support with this project. Lastly, thank you to both Don Mansfield and Vanessa Ashworth for their suggestions that greatly improved this manuscript. Without the assistance and collaboration of so many, this project would not have come to life.  appendix 1 annotated checklist of the vascular flora The following is a checklist of the vascular flora from the Selkirk Mountains of Idaho. This list is a synthesis of fieldwork from 2019 and 2020 by the lead author, as well as an integration of historical collections in the area from the past century. Included historical collections date back to 1901, and are housed at the Stillinger Herbarium (ID), University of British Columbia Herbarium (UBC), Marion Ownbey Herbarium (WS), and the University of Washington Herbarium (WTU). Approximately 2800 collections existed for the area prior to this study, a subset of which were analyzed at ID, along with collections from UBC, WTU, and WS that could not be verified from specimen images. Historical collections were only included if verified by the author, and were clearly collected within the bounds of the study area (Fig. 2). There are 77 collections included in the checklist that were not collected during this study, added to the 768 collected by the study, for a total of 845 taxa (Table 5).
All collections made during the study were identified by the author, unless otherwise noted. Specimen identifications were verified using the Flora of the Pacific Northwest, 2 nd Edition (FPNW), the Flora of North America (FNA), The Jepson Manual (TJM), Sedges of the Pacific Northwest, associated primary literature, and reference collections currently housed at ID (Flora of North America Editorial Committee 1993+; Wilson et al. 2008;Baldwin et al. 2012;Hitchcock and Cronquist 2018). Taxonomy follows the Angiosperm Phylogeny Group (APG) IV classification system (Chase Vascular Flora of the Selkirk Mountains, Idaho For each taxon entry, one reference specimen is cited; individual collection numbers for all collections are not noted but may be obtained online through the Consortium of Pacific Northwest Herbaria (CPNWH 2020). Collections during 2019 followed the numbering convention of 2019-#, and 2020 collections continue the numbering convention without a prefix. A complete set of the specimens collected during the 2019 and 2020 field seasons are housed at ID, and locations of historical collections are noted.
Synonyms are only included if in widespread use in recent floras or literature. Misapplied names are discussed in taxonomic notes for each entry. Common names are based on the original Flora of the Pacific Northwest (Hitchcock and Cronquist 1973) and USDA common names (USDA 2020). Collection and taxonomic notes are provided in brackets in circumstances of confusion or importance, as well as conservation status, if listed.
Distribution and abundance of each vascular plant species within the study area is denoted with either common, locally common, occasional, uncommon, or rare. Defined as follows: rare = 1-3 collection sites, not observed outside the study area and vicinity, State listed; uncommon = narrowly distributed, seldom observed; occasional = variably distributed, infrequently observed; locally common = narrowly distributed, commonly observed within its range; common = broadly distributed, commonly observed in the study area. Vegetation types follow the outlined types for the area discussed earlier.
Plant status is denoted with symbols for rare, non-native and collection significance. Rare is denoted as ( ), and included is the State NatureServe ranking explained earlier, non-native species are denoted with ( †) following designation by FPNW, State-listed noxious species are marked with ( ) following designation by ISPI (Invasive Species of Idaho), and native species are not noted. Native vs. non-native status is defined at the State level, using the USDA Plants Database (USDA 2020). Additionally, State (!) and County (*) collection records are denoted. County presence within the study area is denoted as (BO) for Bonner and (BR) for Boundary and limited to entries with voucher specimens.
Entries based on historical collections do not contain distribution and abundance codifiers, vegetation types, or elevational bands. Historical specimens with vague locality data or just beyond the edge of the study area are included in the Appendix under "Excluded Taxa". The checklist is arranged into larger groups in the following order: Lycopodiophyta (Fern Allies), Monilophyta (Ferns), Coniferae (Gymnosperms), and Angiospermae, first with Nymphaeales (Cabombaceae and Nymphaceae) and Piperales (Aristolochiaceae), then followed by Eudicotyledonae and Monocotyledonae. Included within the list are original scientific illustrations of select species  and the project logo (Fig. 54)