Aliso: A Journal of Systematic and Floristic Botany Aliso: A Journal of Systematic and Floristic Botany

The northern portion of Death Valley National Park closely (but not entirely) corresponds to the northernmost portion of the Mojave Desert in California. From 2014 through 2019 we surveyed the vascular plants in the Eureka Valley, northern Last Chance Range, and northern Death Valley. This study area covers 1735 sq km and ranges in elevation from 810 to 2577 m; it contains the tallest sand dunes in California, a calcium-rich mountain range, and alkaline seeps. These features provide specialized habitats for narrowly and regionally endemic plants. Fossil data from packrat middens suggest that the local climate has become warmer and drier during the Holocene and the assemblage of plants currently observed has only been in place for a few thousand years. During six years of field-work, we documented 542 specimens of minimum-rank taxa, including 51 special concern taxa and 25 non-natives. We were unable to relocate 45 taxa known from historic collections. Fifty-one collections were the first for the study area; these include 24 range extensions. Observations from our collections are combined with those from historic collections and other collectors in an annotated checklist.

Basin and Range topography that covers most of Nevada and eastern California (Eaton 1982).
The study area encompasses this northern portion of DVNP as well as the northwest corner of the EV (Fig. 1).This area nearly corresponds to the northern limits of the Mojave Desert Region and Desert Mountains Subregion of the Desert Province within California (Baldwin et al. 2012) and is bordered by Great Basin Province to the north and west.The Mojave Desert Region continues into Nevada to the east.
The study area covers an area of 1735 sq km.The highest elevation is Last Chance Mountain (called Whitetop by some collectors, because of a patch of white limestone at its summit) at 2577 m and the lowest (810 m) is to the east of LCR in Death Valley.The lowest elevation in EV is the saline playa (877 m) to the west of the main Eureka Dunes.The northern end of Eureka Valley is about 600 m higher and gradually drops in elevation toward the south.Notable features include the Eureka Dunes (south end of the Eureka Valley), a series of seeps and springs associated with the Death Valley-Furnace Creek Fault Zone east of LCR (Strand 1967;McKee 1985;Wrucke and Corbett 1990), and the complex geology (carbonates, basalts, sedimentary formations, sulfur deposits) of LCR.These factors have produced a rich flora that includes narrow endemics (Astragalus lentiginosus var.micans, Boechera yorkii, Eriogonum gilmanii, Oenothera californica subsp.eurekensis, Swallenia alexandrae) as well as a number of regional endemics that are restricted to Inyo County and adjacent counties in Nevada.
The goal of the present study is to summarize previous collection work and to document the occurrences and distribution of vascular plants during the period of 2014 through 2019.The results of this project are presented in an annotated checklist (Appendix 1).Bell,Fig. 4,6,7;Sarah De Groot,Fig. 2,3,5.physical setting

Geography and Road Access Within the Study Area
The study area encompasses the northern portion of DVNP and EV, including the northwest portion of the valley that falls within Piper Mountain Wilderness, Fig. 1.The National Park boundaries define the eastern and northern boundaries (Willow Spring Road between the LCR and Sylvania Mountains Wilderness).The edges of EV up to approx-imately 1250 m form the northwestern, western, and southern boundaries (to Dedeckera Canyon).The intersection of the Big Pine to Death Valley Road with Racetrack Valley Road (essentially 37°N latitude) is the southern boundary of the study area (excluding the hills north of Scotty's Castle).
There are relatively few roads in the study area (Fig. 1); all roads are dirt except for a short portion of the Big Pine to Death Valley Road (BP-DV).

Previous Collectors in the Study Area
The history of botanical exploration in the study area is relatively short.There is no evidence that either Coville (1893) or Gilman (associated with Death Valley National Monument) collected in the study area.Most collecting efforts occurred primarily during the 1950s and 1970s and have focused on the Eureka Dunes and the western slopes of LCR, especially Dedeckera Canyon, as well as Sand Spring in the northern portion of Death Valley.Most notably, Mary DeDecker collected in the area and produced the comprehensive flora (DeDecker 1984).
We obtained information about previous collecting in the study area from the Consortium of California Herbaria database (CCH1/2 2021).Aside from two collections made in 1927, the oldest herbarium specimens from the study area were collected by Annie Alexander and Louise Kellogg, field biologists, on Vascular Plants of Northern Death Valley National Park trips in 1947 and 1949.They collected at Sand Spring on the eastern side of LCR and also at the main Eureka Dunes.Notably, they made the first scientific collection of Swallenia alexandrae (the Eureka Valley dune grass), named for Annie Alexander.In the mid-1950s, Philip A. Munz, director of Rancho Santa Ana Botanic Garden (and authority on Onagraceae), and John C. Roos, a medical doctor from Loma Linda Hospital, collected (both together and separately) in the study area.Drs.Munz and Roos recognized the distinct character of Oenothera californica subsp.eurekensis, a rare, narrow endemic found only on dunes in the Eureka Valley.Bruce Pavlik (1979Pavlik ( , 1988) ) studied the phytogeography of California dunes and was an effective advocate for protection of the Eureka Dunes.Christopher Davidson, Dean Taylor, James Morefield, and James André have all col-lected in the EV and LCR and have contributed many specimens to herbaria throughout the state (Table 1).Dana York, DVNP botanist from 1999 to 2004, added many specimens from the study area to the park herbarium (DEVA) during 2000 and 2001.He made the first collection of a new species of Boechera from the LCR that was named Boechera yorkii in his honor (Boyd 2004).In addition, the California Native Plant Society (CNPS), and particularly, its Bristlecone Chapter, have hosted many field trips to the study area, especially the Eureka Dunes.
The most influential collector in the northern Mojave Desert was Mary DeDecker who made innumerable contributions to the knowledge of California plants and conservation of critical desert habitats.Her work was vitally important to the protection of the Eureka Dunes and to the expansion of Death Valley National Monument to include most of the EV and LCR (and elevation to a National Park).Mary DeDecker recruited help from many academic botanists, including Robert Thorne of Rancho Santa Ana Botanic Garden and Peter Raven of Missouri Botanic Garden, to advocate for protection of the area.Her friend, Mary Ann Henry, began monitoring studies of dune endemics (Henry 1979).DeDecker collected extensively throughout the Owens Valley, eastern Sierra Nevada, and northern Mojave Desert and is the author of Flora of the northern Mojave Desert (DeDecker 1984).In 1975, Mary DeDecker, with her husband, Paul, made a collection of an odd shrub in a canyon east of the Eureka Dunes.This unusual buckwheat (Polygonaceae) was named Dedeckera eurekensis in honor of Mary.A further tribute to her accomplishments came when the type locality of D. eurekensis was named Dedeckera Canyon.Her approximately 6400 specimens were donated to the herbarium of Rancho Santa Ana Botanic Garden (RSA) and her index cards recording detailed observations from her collections are curated by the Bristlecone Chapter of CNPS.

Weather Data for the Study Area
The Eureka Valley weather station (Western Regional Climate Center 2020; station ID: TT184) went online in March 2013 and data are presented in  2013, 2014, and 2015(Scoles-Sciulla and DeFalco 2013, 2014, 2015) are combined with that from TT184 in Table 2. Generally, the rainfall patterns at the dune locations are similar to those recorded by the Eureka Valley weather station (Table 2).Comparison of the two data sets helps to illustrate the patchiness of rainfall in the northern Mojave Desert, with high rainfall sometimes occurring at only one of the four locations in a given month.For October 2013, Scoles-Sciulla and DeFalco recorded 12 mm of rain at Marble Dune but 43 mm at Saline Spur Dune, (no data are available for the main Eureka Valley Dune), while TT184 recorded 7 mm.In contrast, high rainfall occurred at all four locations in August 2014, when Scoles-Sciulla and DeFalco recorded 23 mm at the main Eureka Dune, 32 mm at Saline Spur Dune, and 28 mm at Marble Dune, while TT184 recorded 21 mm for the same period.In July 2015, 5 mm of rainfall was recorded at the Main and Saline Spur dunes, while 14 mm was recorded at Marble Dune and 20 mm at TT184.Hereford et al. (2006) studied the precipitation history and ecosystem responses in the Mojave Desert for the period 1893-2001.They observed two broad patterns: a bi-seasonal pattern (roughly equal amounts of rainfall during winter and summer months) and a winter-dominant pattern.East of 117°W, a biseasonal pattern was recorded by 90% of weather stations; west of 117 º W, 70% of weather stations recorded a winter-dominant pattern.The study area is west of 117°W and can be expected to show a dependence on winter rainfall.The bi-seasonal pattern is  (Scoles-Sciulla and L. DeFalco 2013, 2014, 2015) at the main Eureka Dune (Main), the Saline Spur Dune (Spur), and the Marble Dune (Marble).Rainfall is given in mm; tr = trace (<0.5 mm); n/a indicates periods when readings were not available.due to contributions to the total rainfall from monsoonal storms that originate off the coast of Mexico and travel north along the Gulf of California.However, given that the study area is at the most northern latitudes of the Mojave Desert, the bi-modal distribution of precipitation is attenuated.
In the desert, timing, volume, and distribution of rainfall are extremely important for germination and establishment, especially for winter annuals (Beatley 1967(Beatley , 1974;;Bowers 2005).Table 3 shows the temperature and rainfall data collected by TT184 from 2013 through 2019.For field botanists, these patterns of rainfall determine the availability of plants for collecting, and a patchy distribution of rainfall in our study area (see Table 2) is likely responsible for variation in collection volume during different field seasons.For example, we collected the following numbers of specimens by year: 2014-237, 2015-69, 2016-380, 2017-445, 2018-47, 2019-469.We also observed significant geographical variation in density of available specimens; there were periods when there were large numbers of flowering annuals at the north end of EV while the area around the dunes at the south end of the valley was almost devoid of annuals.In addition, we observed altitudinal variation; LCR receives snowfall almost every year; the depth and persistence of snow contributes to available soil moisture for plant growth at higher elevations and, especially, on northern and eastern aspects.

Geology of the Study Area
The study area is part of the Basin and Range geomorphic province (Eaton 1982) and consists of two graben valleys running northwest to southeast with LCR between them (Fig. 1).The EV is filled with alluvia derived from the Inyo Mountains to the west and LCR to the east.The base rocks of both ranges contain Cambrian marine sediments (limestones, sandstones, silt stones, dolomites, and quartzite); these are overlaid by volcanics, primarily basalts and tuffs (Stewart 1965;McKee 1985;Wrucke and Corbett 1990).The region is crisscrossed with faults, intrusions of granites, and aquifers with resulting complex mineralization (Norris and Webb 1990;Niemi 2002).There have been numerous explorations to locate and extract precious and commercially useful minerals; however, commercial extraction was hampered by lack of water for processing.Gold, silver, copper, lead, and zinc have been found on the east side of the Inyo Mountains.Significant quantities of mercury (El Capitan Mine) and sulfur (Crater Mine) have been extracted from LCR.Small quantities of lead, silver, and gold have been found near Last Chance Spring.The north end of EV and LCR are filled with mine shafts, discarded equipment, exploratory pits, and tailings.For a more detailed description of mining exploration in the study area, see Davis (1993).

Vegetation History of the Study Area
The Mojave Desert is relatively old with respect to geology but relatively young in terms of vegetation.Desertification began with the rain shadow created by the uplift of the Sierra Nevada beginning 25 million years before present (MYA).The rain shadow was well developed at the time of the last glacial maximum (25 thousand years ago, KYA).Although the region defined as Mojavean was never covered with ice, the climate was cooler and the northern Mojave was covered with mesic wood-land vegetation (Baldwin et al. 2012).As the glaciers receded, the region became drier and warmer.Woodland vegetation was displaced to higher elevations or north-facing exposures or extirpated.Xerophytic shrubs dispersed northward.
The vegetation of the EV changed dramatically during the Holocene (10 KYA;Spaulding 1980Spaulding , 1990)).The packrat midden record documents displacement of juniper woodlands from lower elevations and the slow immigration of heat-tolerant shrubs to replace trees.Midden data from the north end of EV (south-facing dolomite slope and talus, elevation 1390-1555 m, Eureka View site, Fig. 1) describes the vegetation as juniper-shadscale (Juniperus osteosperma-Atriplex confertifolia) woodland at 14.7 KYA.In addition to these dominant species, Ephedra cf.viridis, Hecastocleis shockleyi, and Artemisia spp.were found in the oldest deposits.Juniper was not found in younger deposits and, at the present day, can be located on the north and east sides of LCR above 1500 m.Ephedra, H. shockleyi, and Artemisia can be found close to the Eureka View site at similar elevations but on north-facing exposures.Shadscale persists to the present day at and near the midden site.
Some current-day dominants did not appear in the midden fossil record until much later (Spaulding 1980(Spaulding , 1990)); Ambrosia dumosa appeared at 6.8 KYA, and Larrea tridentata arrived between 5.6 and 3.9 KYA.Eriogonum fasciculatum appeared at 1.6 KYA.

Descriptions of Vegetation Types
It is not easy to divide the vegetation in the study area into discrete categories.The alliances and associations that we have observed do not fit neatly into the categories described by Sawyer et al. (2009).We are using their format with modifications to describe the vegetation in the study area.These descriptions are used to define the habitat categories in the checklist (Appendix 1).Not all associated taxa are found at all the sites where a habitat category is used and many associates are found in more than one vegetation type.On the other hand, several of the associations we describe apply only to a single site within the study area.
Larrea tridentata-Ambrosia dumosa Shrubland.-Creosotebush is the most abundant taxon within the study area.Thousands of individuals and some clones (Vasek 1980) are found throughout the Eureka Valley and in the northern portion of Death Valley.There are very arid areas in the center of the Eureka Valley where creosote is sparse and depauperate and few other shrubs and winter annuals are observed.Generally, larger individuals of creosote and a larger number of associated species are found at the north end of the Eureka Valley and on the east side of Last Chance Range.Within the study area, creosote is found below 1500 m in elevation.Ambrosia dumosa (bursage) is the most common associate of creosote and is found throughout its range in the study area.

objectives and methods
The objective of this project was to document the presence and distribution of vascular plants in the northern portion of Death Valley National Park and the adjacent portion of EV (see Fig. 1).We combined information about historic collections obtained from the Consortium of California Herbaria (CCH1/2 2021) with collections made from 2014 through 2019.Specimens from this study are deposited at DEVA and RSA.
We collected on 65 days in six field seasons from 2014 through 2019.We attempted to recollect all taxa known from historic collections (CCH1/2 2021).Previous field work in the study area was primarily at the main Eureka Dune and surrounding area, Dedeckera Canyon, and the springs on the east and north sides of the LCR (especially Sand Spring).We focused collection efforts on the areas north of the BP-DV Road (in the Eureka Valley), the northern portion of LCR, and Last Chance Canyon.We recorded locality data with a Global Positioning System (GPS) device, as well as habitat descriptions, local abundance, and associated taxa.Cacti were processed following the methods of De Groot (2011).
The following keys were used for plant identification: Baldwin et al. (2012), Jepson eFlora (Jepson Flora Project 2020), Flora of North America (1993+), Simpson and Hasenstab (2009), and Morin and Ayers (2020); in addition, we relied heavily on comparisons with the general and synoptic collections of RSA at California Botanic Garden (formerly Rancho Santa Ana Botanic Garden).Fortunately, many of Mary DeDecker and John C. Roos' collections are housed at RSA and we were able to examine those.In addition, we were able to examine collections (especially those of D. York) at DEVA.
This work represents a first report on the vascular plants of the study area.Steve Schoenig is leading on-going efforts to further explore the entire Last Chance Range, particularly the southern portion.

Summary Statistics
We collected 1635 specimens over 6 field seasons.These collections represent 67 families and 542 minimum rank taxa (including historic collections).Table 4 summarizes the results of this study.Of these collections, 51 were the first collection of that taxon from the study area; of these first collections, 24 represent range extensions.First collections from the study area and range extensions are noted in the relevant taxon descriptions.
Table 5 compares the results of our study with studies done in the Adobe Hills (Winitsky 2019), White (Morefield et al. 1988), Cottonwood (Peterson 1984), and Grapevine (Kurzius 1981) mountains.Although these studies vary greatly in area and elevation gain, there are similar patterns: Asteraceae are the largest family and Eriogonum the largest genus in all the studies.Poaceae are either 2 nd or 3 rd largest family in all the studies.Cryptantha s.l. and Astragalus are among the five largest genera in all the studies.The present study, Adobe Hills, Cottonwood, and Grapevine Mountains are similar in highest elevation (2444 to 2728 m); the White Mountains are almost twice as tall at 4342 m.In absolute numbers, the White Mountains flora has the largest number of taxa (1078) and covers the largest area (2010 sq km).However, proportionally, the Adobe Hills flora has the greatest density of taxa: 395 taxa on 241 sq km.The Cottonwood and Grapevine Mountains are quite similar; they share the same five most numerous families and four of five largest genera (Phacelia is more numerous in the Cottonwoods and Gilia in the Grapevines; see Table 5).The five largest families in each area account for slightly less than half of the total number of taxa found in each study.

Special Concern Taxa
Assignment as special concern was determined in relation to the CNPS Rare Plant Ranks (CRPR; CNPS 2021b) of the CNPS Rare Plant Inventory (CNPS 2021a); 9.4% of the taxa on the Annotated Checklist are considered special concern and are designated by the symbol §.Nine taxa are considered by CNPS as rare throughout their ranges (1B); 23 are considered to be rare within California but common outside of California (2B) (Table 6).
In 1978, two narrow endemics (Oenothera californica subsp.eurekensis and Swallenia alexandrae) from the Eureka Dunes were listed as endangered under the Endangered Species Act (as Amended 1983).The Bureau of Land Management administered the dunes at that time and BLM was tasked with developing a recovery plan for these species.Mark Bagley (1988) established monitoring plots for S. alexandrae, O. californica subsp.eurekensis, and Astragalus lentiginosus Douglas var.micans Barneby on the Eureka Dunes.After 1994, when the dunes and most of EV and LCR were added to Death Valley National Park, park botanists Dana York, Michèle Slaton, and Jane Cipra (with other park personnel and volunteers) continued monitoring of the dune endemics.In 2018, the U.S. Fish and Wildlife Service delisted O. californica subsp.eurekensis and downlisted S. alexandrae to threatened (USFWS 2018).However, CNPS considers both species, along with A. lentiginosus var.micans, to be rare and endangered (1B.2) because of their narrow distributions (CNPS 2021a).

Historic Collections Not Relocated
We were unable to relocate 45 taxa previously collected within the study area (Table 7).These taxa are designated by in the checklist.Nine are CRPR listed (CNPS 2021a).Importantly, half are specimens collected by J.C. Roos during several trips in 1955.Bowers (2005) identified the mid-1950s as a period with abundant spring flowering annuals.As these specimens are the only record that these taxa occurred in the study area, we hope that further explorations of the LCR will reveal additional populations.

Non-Native Taxa in the Study Area
Less than 5% of the taxa in the study area are non-native.These taxa are listed in Table 8 along with their California Invasive Plant Council inventory rating (Cal-IPC 2021), the study area habitats where they are found, and our observations.Cal-IPC ratings (High, Moderate, Limited) are based upon statewide evaluations of these species' environmental impacts.We give our assessments of the impacts of these taxa in the study area.Based upon our observations, two can be described as rapidly spreading and degrading the habitats where they occur: Salsola paulsenii and Halogeton glomeratus.Salsola paulsenii is common around the Eureka Dunes, especially along the east side of the dunes where they are dominant in some places.Dead plants and fragments of plants are frequently found tangled in hummocks of Swallenia alexandrae and other native plants on the dunes.Halogeton glomeratus is expanding its coverage around the large sulfur mine at Crater and is present 4 km north at the El Capitan Mine sites.Both S. paulsenii and H. glomeratus are also abundant along the North Eureka Valley Road at the mouth of Cucomungo Canyon.
Another non-native taxon of concern is Tamarix.The saltcedar in the study area is probably the widespread T. chinensis × ramosissima hybrid or the hybrid back-crossed with T. chinensis (Gaskin and Schaal 2002;Gaskin and Kazmer 2009).
It was collected three times: in Last Chance Canyon and at two seeps east of Last Chance Spring.Although it is not common in the study area, there should be concern about potential increase at its current sites and/or spread to other nearby seeps.
Several grasses, Bromus spp.and Schismus spp., are widespread in the study area.They have the potential to compete with native annuals (Beatley 1967) and to spread wildfires (Brooks 1999;Fusco et al. 2019).
Other non-natives are present at much lower densities and do not appear to impact native species or to change or dominate landscapes (Table 8).

Taxa Excluded from the Checklist
Whenever possible we examined historic collections from the study area that are cited in CCH1/2 (2021); fortunately, many of these are housed at RSA.There were a few specimens that were difficult to determine to species and other specimens we could Vascular Plants of Northern Death Valley National Park Table 8.Non-native species collected in the study area, habitats where found, and our observations.Cal-IPC (California Invasive Plant Council) ratings of High, Moderate and Limited evaluate the ecological impact of a taxon across California natural areas.

Taraxacum officinale
Found in the disturbed area near Last Chance Spring not locate.Also, there were specimens whose occurrence in the study area was disjunct from their known distribution.We have excluded these specimens from the checklist.However, we want to encourage specialists to seek out and examine them so that they can be correctly identified (Table 9).

discussion
The study area has a density of vascular plant taxa that is comparable to other surveyed areas in the region (Grapevine Mountains [Kurzius 1981]; Cottonwood Mountains [Peterson 1984]; White Mountains [Morefield et al. 1988]; Adobe Hills [Winitsky 2019]; Table 5).We have documented diversification in Asteraceae, as well as Eriogonum, Cryptantha (s.l.), Astragalus, Gilia, and Phacelia.We collected 51 taxa designated as threatened or watchlist by CNPS (2021a) and documented 24 range expansions.However, we were unable to locate 45 previously collected taxa, some of which have not been collected since 1955.
The study area contains a suite of geologic features (sand dunes, seeps and springs, a calcareous mountain range overlain by volcanic deposits) conducive to the evolution of plants adapted to very specific habitats (i.e., endemics).Fossil data from packrat middens suggest that the local climate has become warmer and drier during the Holocene, and the assemblage of plants currently observed has only been in place for a few thousand years.This already rapid desertification has been combined with accelerating rates of human-induced climate change; plants and animals are faced with highly variable temperature and rainfall regimes.Stebbins and Major (1965) identified the northern Mojave Desert (roughly eastern Inyo County) as a region having relatively high endemism as well as a high proportion of relictual species.Population biology has been examined for only a few of the endemics from the study area: low recruitment and low genetic diversity was found in Dedeckera eurekensis (Wiens et al. 2002) and low genetic diversity was found in Swallenia alexandrae (Bell 2013).However, Pavlik and Barbour (1988) deter-Table 9. Taxa excluded from the checklist.Taxa were excluded if we were unable to examine specimens and/or the specimen is disjunct from its main area of distribution and/or characters were ambiguous.mined that while recruitment is infrequent in S. alexandrae, the plants are relatively long lived and the seeds persist in the seed bank.
There are relatively few non-native species on the checklist.However, several of these are becoming more widespread and threaten habitats previously occupied solely by native plants.Salsola paulsenii is well established along the southeast side of the main Eureka Valley dune.The same wind patterns that create and maintain the dunes push plants and plant fragments over the dunes where they become trapped in native vegetation, especially hummocks of S. alexandrae.Relatively few mature plants of S. paulsenii are observed on the dunes, but the plant fragments disintegrate slowly and can alter the local substrate composition and nutrient balance under native plants.Salsola paulsenii (along with Halogeton glomeratus) is ubiquitous at roadsides at the mouth of Cucomungo Canyon (see Fig. 1).Vehicular traffic along North Eureka Valley Road as well as runoff flowing down Willow Wash makes control of these invasive weeds very difficult.Tamarisk was observed at three seeps on the eastern side of LCR.Its ability to spread is probably limited by the overall dryness of the landscape, but it does have the potential to alter native habitat and to disperse to other seeps by occasional high winds.A few non-native grasses are relatively widespread in the study area.Such grasses, especially Bromus spp., have the potential to form a dense understory below native shrubs and Y. brevifolia.A build-up of dried grasses can contribute to the spread of wildfires even in areas of sparse vegetation (Brooks 1999;Fusco et al. 2019).Non-native species compete with native taxa for water and soil nutrients.
Yucca brevifolia is an iconic, widespread symbol of the Mojave Desert that is gradually migrating northward.It is common along Willow Wash Road and North Eureka Valley Road as it enters Fish Lake Valley.CCH1/2 (2021) list a single collection of Y. brevifolia from Mono County (made by J. Morefield in 1987 from the northeast end of the White Mountains).This specimen and 18 others have been recently resurveyed with GPS and documented in iNaturalist, https://www.inaturalist.org/projects/california-s-northernmost-joshua-trees(J.Morefield, pers. comm.).Climate change (natural and human induced) has shaped the flora of the northern Mojave Desert.Even in this relatively remote corner of California the landscape has been altered by human activities: mineral exploration, road building, recreation, and introduction of non-native plants and animals.This checklist will be a record of plant distributions during a brief period in the history of the evolving Mojave Desert.acknowledgements This project would not have been possible without the support and encouragement of Lon Bell.Carol Annable helped to get the project started and provided much-needed practical advice.
We are grateful for assistance from the following Death Valley National Park personnel: Josh Hoines, Drew Kaiser, Lucy Ellis, Carol Fields, Ambre Chaudoin and Michèle Slaton.We especially acknowledge Jane Cipra for her assistance with the permitting process, Jane Lakeman for facilitating access to the DEVA herbarium, and Dana York for providing a list of his collections from the study area.
Leroy Gross, J. Travis Columbus, Dylan Cohen, Duncan Bell, and J. Mark Porter helped with plant identification.Kristen Hasenstab-Lehman, Michael Simpson, Naomi Fraga, and Carolyn Ferguson assisted with taxonomic issues related to their areas of expertise.California Botanic Garden (formerly Rancho Santa Ana Botanic Garden) provided herbarium access (Mare Nazaire) and library support (Irene Holiman and Rachel Poutasse).Joy England gave us helpful comments on an earlier draft.We are grateful to James Morefield for his careful reading of the manuscript; his detailed suggestions improved the final appendix 1 ANNOTATED CHECKLIST This checklist follows the classification of Baldwin et al. (2012) with changes in nomenclature provided by the Jepson eFlora (Jepson Flora Project 2020); Phrymaceae: Barker et al. (2012), Fraga (2012); Cryptantha sensu lato: Hasenstab-Lehman and Simpson (2012); Boraginales (Luebert et al. 2016); Polemoniaceae: Porter and Patterson (2015); Nemacladus: Morin and Ayers (2020); and Amaryllidaceae and Amaranthaceae (Stephens 2001 onwards).Families are listed alphabetically within the conventions of Baldwin et al. (2012): Ferns, Gymnosperms, Magnoliids, and Angiosperms (divided into Eudicots and Monocots).Relative abundance is derived from multiple sources: Baldwin et al. (2012), CNPS Inventory of Rare and Endangered Plants (CNPS 2021a), and Calflora (2019).Synonymy is given if nomenclature has changed since Baldwin et al. (2012).
Special concern is assigned based upon inclusion in the CNPS Rare Plant Inventory (CNPS 2021a) and utilizes its CRPR rankings (CNPS 2021b): Distribution: 1A presumed extinct or extirpated in California, 1B rare throughout their range, 2A extirpated in California but common elsewhere, 2B rare in California but common elsewhere, 3 generally problematic taxonomically and lacking information to assign to a rank, 4 plants with a limited distribution throughout California, watchlist; Threats: 0.1 seriously threatened in California, 0.2 moderately threatened in California, 0.3 not very threatened in California.
Specimens cited in the checklist were chosen based upon their occurrence in representative habitat.We include a very brief description of diagnostic characters with the hope that the checklist will be helpful to visitors to the study area.For a list of bryophytes from the study area, please see De Groot (2022, this issue).

The checklist is formatted as follows:
Scientific name Authority.Common Name.Habit (annual, perennial, etc.) Fig. 1.Map of Eureka Valley, northern Last Chance Range and northern Death Valley, showing main roads, features, and land management.Plant collection sites are shown on the inset satellite image at upper right.Recent collections (by us or others) were made during 1990 or later; historic collections are from before 1990.Locality data were obtained from georeferenced specimen records in the Consortium of California Herbaria (CCH1/2 2021) online data base.Feature names and peak elevations were obtained from USGS topographic quadrangle maps; some place names for collection localities are informal.The Death Valley-Furnace Creek fault zone was drawn based on the Geologic map of California (Jennings et al. 2010).Map created in Esri® ArcMap TM 10.7.1.11595.Map base layers were open source or included with the software; sources: Bureau of Land Management (Land Status geodatabase version 10, 2019), Owlshead GPS (roads), http://owlsheadgps.com/but original sources from public land management agencies), Esri (World Hillshade and World Imagery basemaps, credits on maps).

Fig. 8 -
Fig. 8-13.Last Chance Range.-8.View to the east of exposed limestone at summit of Last Chance Mountain (Whitetop), stunted pinyonjuniper woodland on the south-facing slope.-9.View to east from a basalt-capped hill (foreground) south of Crater; on the left: tilted limestone formations; on the right: eroded sedimentary hills.-10.Volcanic mesa just south of Big Pine-Death Valley Road with desert scrub.-11.Seep southeast of Last Chance Spring with blackbrush scrub and patches of pinyon-juniper woodland.-12.Calcareous rock outcrop with typical vegetation including Buddleja utahensis and Glossopetalon spinescens.-13.Main shaft of El Capitan Mine north of Crater, surrounded by desert scrub dominated by Ericameria nauseosa.Photos: Sarah De Groot.

Fig. 14 -
Fig. 14-19.Eureka Valley.-14.View of Eureka Valley from the north looking toward the main Eureka Dune in far distance.-15.View to the west toward Marble Dune in a notch in the Saline Range.Inyo Mountains are in background.-16.View to the north from the east side of main Eureka Dune in April 2016 after a dry fall and winter.-17.View to the south from the east side of main Eureka Dune in April 2014 after adequate fall and winter rains, with abundant Sphaeralcea ambigua.-18.View to the north from south end of the main Eureka Dune, dark green bushes are Salsola paulsenii (note stratifications on Last Chance Range).-19.Snow on Last Chance Range, May 2019.Photos: Hester Bell, Fig. 15-18; Sarah De Groot, Fig. 19; Deborah Woo, Fig. 14.
Table 2 for 2013-2019.TT184 is located approximately 6.5 km south of the BP-DV and 4 km west of the South Eureka Valley Road.It complements the weather stations at each of the dune locations in the Eureka Valley-the main Eureka Dune (Main), the Saline Spur Dune, and Marble Dunethat were installed by Sara Scoles-Sciulla and Lesley DeFalco of the US Geological Survey in 2012.TT184 is approximately 13 km from the main Eureka Dune, 5 km from Marble Dune, and 8 km from Saline Spur Dune.Rainfall data for

Table 2 .
Recorded rainfall from 2013 through 2019.Comparison of the Eureka Valley weather station (TT184) and the temporary weather stations
(McKee 1985;Norris and Webb 1990;Wrucke and Corbett 1990;Knott et al. 2014)rekensis, Diplacus rupicola, Enceliopsis nudicaulis, Eremogone macradenia var.macradenia,Eriogonum fasciculatum var.polifolium,E.gilmanii,E.heermannii,E.umbellatumvar.versicolor,Fendlerellautahensis,GlossopetalonspinescensVascular Plants of Northern Death Valley National Park var.aridum,Penstemon calcareus, Phacelia perityloides var.perityloides,Phacelia rotundifolia, Salvia funerea, Sclerocactus polyancistrus, and Scopulophila rixfordii.Dicoria canescens-Abronia turbinata Sparsely Vegetated Alliance.-Thisalliance is found on and at the margins of the Eureka Valley dunes.This alliance is surrounded by Larrea tridentata-Ambrosia dumosa Shrubland.Dicoria canescens is found in the deeper sand of the dunes proper, along with Corispermum americanum, Ericameria nauseosa var.ceruminosa,Stipa hymenoides, Swallenia alexandrae, Tiquilia plicata.Abronia turbinata grows at the margins of the dunes along with: Astragalus lentiginosus subsp.micans,Baileyapleniradiata,Carsoniasparsifolia,Lupinusshockleyi,Malacothrixsonchoides,Oenothera californica subsp.eurekensis,O.primiveris,Psorothamnuspolydenius,Sphaeralceaambigua.There is a severe infestation of Salsola paulsenii at the southeast edge of the main Eureka Dune.Atriplex spp.-Suaeda nigra Shrublands.-The lowest part of the Eureka Valley is found northwest of the main Eureka Dune in an area called the Playa.The Playa has highly alkaline and saline soils that support a narrow range of taxa, mostly members of Amaranthaceae.These include: Atriplex canescens var.laciniata, A. polycarpa, A. truncata, Salsola paulsenii, and Suaeda nigra.There are riparian habitats associated with three seeps/springs in the study area; they are all associated with the Death Valley-Furnace Creek fault zone(McKee 1985;Norris and Webb 1990;Wrucke and Corbett 1990;Knott et al. 2014).As the only sources of surface water for great distances, most of the seeps have been utilized by humans and animals and are almost always highly disturbed.Alkaline seep with Distichlis spicata, Phragmites australis, and Schoenoplectus americanus.-Thelargestseep is Sand Spring (1015 m in elevation, with Little Sand Spring) located at the north end of Death Valley on the east side of the Big Pine to Death Valley Road.Sand Spring arises in sparse creosote scrub from a base of sandy, gravelly, slightly consolidated alluvium.The white-crusted soils surrounding Sand Spring are highly alkaline and saline due to accumulated minerals left by evaporation at the exposed, west-facing site.A large portion of Sand Spring has been fenced to restrict access by wild burros.Species found there include: Anemopsis californica, Carex praegracilis, Eleocharis rostellata, Epipactis gigantea, Glycyrrhiza lepidota, Heliotropium curassavicum, Juncus mexicanus, Phragmites australis, Prosopis glandulosa var.torreyana (a large specimen that died between 2018 and 2019), Sisyrinchium funereum, Solidago confinis, and Vitis girdiana.Riparian habitats associated with Last Chance Spring.-Acomplex of seeps is found on the east side and north end of LCR.These are generally more sheltered from evaporation and are less alkaline than Sand Springs or Willow Springs.The largest is Last Chance Spring (1770 m in elevation) that arises from bedrock in a narrow east-west running canyon of the east side of LCR.There are several abandoned mine shafts in the canyon and, clearly, miners have lived in the canyon at various times.Distinct suites of plants are found at the main spring, at the seep on a south-facing slope at the mouth of the narrow canyon, and at the small seeps in surrounding washes.Last Chance Spring is surrounded by pinyon pine woodland with Artemisia, Coleogyne, and Juniperus close by.At the main Last Chance Spring, several species may have been deliberately (or inadvertently) introduced by humans: Asparagus officinalis, Juglans hindsii, Medicago lupulina, and Vitis californica.In addition, these native taxa were observed: Baccharis sergiloides, Cirsium mohavense, Eleocharis macrostachya, E. parishii, Epipactis gigantea, Primula pauciflora, Salix lasiolepis, Solidago confinis, and Vitis girdiana.The following taxa were found at the south-facing seep at the mouth of the canyon: Atriplex canescens, Artemisia spp., Castilleja minor, Elymus condensatus, Epipactis gigantea, Ericameria nauseosa.Gutierrezia, Juncus, Sarcobatus vermiculatus, Schoenoplectus californicus, Sisyrinchium funereum, Sporobolus airoides, and Thelypodium integrifolium.At the small seeps in surrounding washes, combinations of the following taxa were found: Eleocharis, Elymus triticoides, Equisetum laevigatum, Muhlenbergia asperifolia, Nasturtium officinale, Prosopis glandulosa var.torreyana,Rosa woodsii, and Salix exigua.Alkaline seep with Salix lasiolepis.-WillowSpring (1775 m in elevation) is directly adjacent to Willow Spring Road in Cucomungo Canyon at the north end of LCR and the national park border.It is highly disturbed by free-range cattle.There is evidence of accumulated minerals at Willow Spring; however, much less than at Sand Spring.Willow Spring is surrounded by Pinus monophylla-Yucca brevifolia Woodlands (as well as the abundant shrubs, Artemisia tridentata and Ericameria nauseosa).This site is dominated by Salix lasiolepis; the following taxa (at much lower densities) were also observed: Amaranthus blitoides, Calyptridium monandrum, Cardamine oligosperma, Cryptantha pterocarya var.cycloptera, Dysphania botrys, Elymus cinereus, Eremothera boothii subsp.alyssoides, Juncus balticus, J. bufonius var.bufonius, Ranunculus cymbalaria, and Typha domingensis.

Table 4 .
Baldwin et al. (2012)rthern Death Valley National Park Summary of known collections from the study area.The majority were made by us from 2014 to 2019.Life forms: annuals (235) 43%; perennials (197) 36%; shrubs (103) 19%; trees (8) 1%.Twenty-two families were represented by a single taxon, while ten families accounted for 67% of total collections.Group headings followBaldwin et al. (2012).The California Rare Plant Rank (CRPR) listings are from the California Native Plant Society Inventory of Rare and Endangered Plants.The two columns to the right contain numbers for historic collections not relocated during the current study and recent collections by other collectors (historic: before 1990; recent: 1990 and after).

Table 5 .
Comparison of several floristic, collection-based studies from eastern California and western Nevada.These studies varied in the size of the study areas, topography, and the time frame of the project.Taxonomy is not uniform between the studies and affects Cryptantha s.l.

Table 6 .
Special concern taxa (rare, endangered, and watchlist)in the study area.Rarity status is derived from the California Native Plant Society (California Rare Plant Rank) and the State and Federally Listed Endangered, Threatened, and Rare Plants of California (CNDDB, July 2021).

Table 7 .
Taxa that were not relocated during the present study.We give the number of collections that were located in searches of the CCH1 and CCH2 databases (CCH1/2 2021), the last year collected, and, if applicable, CRPR status.With the exception of one collection by P. Munz, all the collections from 1955 were made by J.C. Roos.