Phyllanthus novofriburgensis and P. pedrosae , two new species of Phyllanthus subsect. Clausseniani (Phyllanthaceae) from Southeastern Brazil

. Phyllanthus novofriburgensis J.C.R.Mendes, J.M.A.Braga & Fraga sp. nov. and P. pedrosae J.C.R.Mendes, J.M.A.Braga & Fraga sp. nov. are new species of Phyllanthaceae described from the Brazilian Atlantic Forest and Brazilian Cerrado, respectively. Phyllanthus novofriburgensis resembles P. acutifoliu s Poir. ex Spreng., P. hypoleucus Müll.Arg. and P. lilliputianus J.C.R.Mendes, J.M.A.Braga & Fraga, sharing ovate, elliptical, and lanceolate leaf blades. However, it can be distinguished by its pendulous habit, often with sinuous branches and lanceolate leaf blades with characteristically revolute margins. Phyllanthus pedrosae exhibits morphological similarities with P. claussenii Müll.Arg. due to its subshrubby and prostrate habit. It is distinghuished by the unisexual inflorescence with cymules composed of one or two staminate flowers proximally positioned in the axil of the branches and solitary pistillate flowers distally situated, and the 5-merous calyx in the staminate and pistillate flowers. Both new species are classified in Phyllanthus subgen. Phyllanthus sect. Phyllanthus subsect. Clausseniani G.L.Webster, primarily due to the deeply emarginate anthers. Notes on their geographical distribution and habitat are provided, as well as a key to the species of Phyllanthus from Southeastern Brazil.


Introduction
During the last decades, approximately 1270 species were recognized in Phyllanthus s.l.(Phyllanthaceae), making it one of the giant pantropical genera of angiosperms, with more than 50 sections and almost 20 subsections (Kathriarachchi et al. 2006;Bouman et al. 2018).However, with the recent split of the Phyllanthus s.l. in 18 genera based primarily on molecular phylogenetic data, the number of species in this genus has been reduced to just over 200 species, mainly occurring in the American continent, distributed into five subgenera, 24 sections and seven subsections (Bouman et al. 2022).The newly circumscribed genus Phyllanthus is characterized by its phyllanthoid or non-phyllanthoid branching, monochlamydeous flowers without pistillodes, and with a segmented nectariferous disc in staminate flowers and an entire nectariferous disc in pistillate flowers, and seeds differently ornamented (Bouman et al. 2022).
In recent years, five new species were discovered in subsection Clausseniani, which were all restricted to microhabitats in mountainous regions with altitudes ranging from 1000 to 1600 m and rugged topography where they grow on rocky outcrops or slopes, in litholic or sandy soils (Torres et al. 2020;Mendes et al. 2021Mendes et al. , 2022)).In these same environments of rocky outcrops and slopes, two additional species of subsection Clausseniani were discovered in the rocky landscape in the Atlantic Forest from Rio de Janeiro and in Cerrado (savanna) from Minas Gerais, both Brazilian states.In this paper, we provide morphological descriptions, illustrations, an identification key for Phyllanthus species occurring in Southeastern Brazil, a map with occurrence records, an assessment of the conservation status, and taxonomic notes.

Material and methods
The study was based on the analysis of specimens deposited in the herbaria OUPR, MBML, PEUFR and RB (acronyms according to Thiers 2023), including Mendes's recent collections used as type in this study.Measurements and other traits (e.g., geographic distribution and phenology) provided in the descriptions are based on the analysis of herbarium specimens and on populations studied in the field.The morphological terminology follows Webster (2002) and Beentje (2016).The distribution map was generated in QGis ver.3.16.(QGIS Development Team 2020).The preliminary conservation status was assessed according to IUCN guidelines and criteria (IUCN 2022) complemented by the online geospatial conservation assessment tool (GeoCat), which was used to calculate the extent of occurrence (EOO) and area of occupancy (AOO), with a user-defined cell of 2 km 2 (Bachman et al. 2011).

Etymology
The specific epithet is based on the type locality.

Distribution, habitat and phenology
Phyllanthus novofriburgensis sp.nov. is found in the phytogeographic domain of the Atlantic Forest in the city Nova Friburgo, state of Rio de Janeiro, Brazil, growing under rocky walls (inselberg), in altitudinal ranges between 868 and 1267 m (Fig. 3).It was collected with flowers and fruits in September, October and November and only with flowers in February.

Preliminary conservation assessment
Phyllanthus novofriburgensis sp.nov.falls into the Critically Endangered (CR) category, sub-criterion B1+B2 ab(iii,iv), due its range size (EOO) of 7 km 2 and AOO of 4 km 2 .We classified it in this category because the species is restricted to a single rocky wall where an old train line is located.The surrounding area faces intense demographic pressure and anthropization.Consequently, we anticipate an imminent threat to the conservation of P. novofriburgensis.

Distribution, habitat and phenology
Phyllanthus pedrosae sp.nov. is found in the phytogeographic domain of Cerrado in the city of Ouro Preto, state of Minas Gerais, Brazil, growing on slopes of rocky outcrops, close to watercourses in the Parque Estadual do Itacolomi, in altitudinal ranges between 1470 and 1600 m (Fig. 3).It was collected with flowers and fruits in May and November; and with flowers in May and June.

Preliminary conservation assessment
Phyllanthus pedrosae sp.nov. is categorized as Critically Endangered (CR), sub-criterion B2ab(ii,iv) due to its AOO of 4000 km 2 .Although this species has abundant populations and is inserted in the context of a protected area, we believe that the species faces many threats due to the uncontrolled deforestation process in the surroundings of the Parque Estadual do Itacolomi and because the region is heavily visited by tourists.Minas Gerais.Phyllanthus pedrosae has the greatest morphological affinity with P. caparaoensis; they are the only species in Phyllanthus sect.Phyllanthus subsect.Clausseniani that present angular stems and branches.However, P. pedrosae is easily separated from P. subemarginatus and P. caparaoensis mainly by morphological characteristics such as the shape of the stem and branch, inflorescence, the disc surface of staminate flower, the dehiscence of the anther and the size of the fruiting pedicel, as shown in Table 2. Phyllanthus pedrosae is found in the same environment as P. fastigiatus Mart.ex Müll.Arg., but the latter is easily recognized by its dense branches at the apex of the stem, elliptical to obovate leaf blades, and 3 connate stamens.Differences between congener species are summarized in Table 2.