Two new species of Psyllocarpus (Spermacoceae, Rubiaceae) from the state of Minas Gerais, southeastern Brazil Key to the species of Psyllocarpus sect. Psyllocarpus , Two new species of Psyllocarpus (Spermacoceae, Rubiaceae) from Brazil

. Two new species of Psyllocarpus sect. Psyllocarpus , P. itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov. and P. vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov., from the “campo rupestre” of the state of Minas Gerais, southeastern Brazil, are here described and illustrated. We provide comments on their distribution, habitat, and preliminary conservation status, and discuss their taxonomy. In addition, we analyse floral, fruit, and seed micromorphology, as well as pollen grains of the new species. We also provide an updated identification key to the species of P. sect. Psyllocarpus . Two new species of Psyllocarpus (Spermacoceae,


Introduction
The two remaining species described in Psyllocarpus (P. intermedius E.L. Cabral & Bacigalupo (Cabral & Bacigalupo 1997) and P. densifolius Zappi & Calió (Zappi et al. 2014)) were not included in any section, as they present morphological features divergent from those of P. sect. Psyllocarpus, despite occurring in the same geographical region. More recently, Carmo et al. (2021) have recognized the new monotypic genus Diadorimia J.A.M. Carmo, Florentín & R.M.Salas to accommodate P. densifolius, while molecular phylogenetic analyses have indicated that P. sect. Psyllocarpus would appear to be monophyletic with maximum to high support, even though sampling was low (Salas et al. 2015;Florentín et al. 2017;Miguel et al. 2018), pending further investigation to test the monophyly of the genus as currently circumscribed, as well as its sections.
The analysis of specimens collected in the state of Minas Gerais, southeastern Brazil, have revealed that these do not correspond to any described species in Psyllocarpus, and are in fact new to science. As a part of our revision of the genus, we describe here two new species of Psyllocarpus sect. Psyllocarpus. We provide their descriptions, illustrations, and photographs, as well as comments on their distribution, habitat, preliminary conservation status, and taxonomy. Micromorphological characteristics of flowers, pollen grains, fruits, and seeds are also described and illustrated. We also provide an updated key to the species of P. sect. Psyllocarpus.

Material and methods
This study is based on field collections and analysis of specimens deposited at the BHCB, CTES, and UEC herbaria (acronyms of herbaria follow Index Herbariorum (Thiers continuously updated)). For descriptions and morphological comparison, we used conventional taxonomic methods. We followed the Systematics Association Committee for Descriptive Biological Terminology (1962), Clopton (2004), and Simpson (2010) for general morphological terminology, and Weberling et al. (1997) and Rua (1999) for inflorescence terminology. The distribution map was created using QGIS ® software (QGIS Development Teams 2021). A preliminary conservation status assessment was carried out by range size (B criterion), following the IUCN Standards and Petitions Committee (2019) recommendations. The extent of occurrence (EOO) and area of occupancy (AOO) were estimated using GeoCAT (Bachman et al. 2011). Pollen grains were acetolyzed according to Erdtman (1966) and mounted in glycerine jelly for analysis using a light microscope (LM). Conventional parameters (polar (P) and equatorial (E) axis, apertures, exine) in at least 20 mature grains were measured under LM and the exine details (architecture and ornamentation) were analysed using scanning electron microscopy (SEM). The terminology used to describe the pollen followed Punt et al. (2007). Fresh buds, mature flowers, fruits, and seeds fixed in alcohol 70% were also analysed using SEM. We used the terminology proposed by Stearn (1986) for seed descriptions. For the images, the dehydrated material and acetolyzed pollen grains were sputter-coated with gold and then photographed with a Jeol 5800 LV SEM (SGCyT -UNNE, Corrientes, Argentina). , inflorescences in terminal glomerules, rarely with axillary inflorescences in 1-flowered cymes (vs axillary inflorescences in 1-flowered cymes), corolla tube 1.78-2.08 mm long (vs 2.9-6.7 mm long), calyx tube absent to vestigial (vs present), and seeds broadly obovate in outline (vs elliptic to broadly elliptic in outline).

Etymology
The specific epithet refers to the municipality of Itacambira, in the state of Minas Gerais, where the species is found. ʻItakangapyraʼ means ʻstone with a pointed headʼ and derives from the ancient Tupi, an extinct Tupi language that was spoken by the Tupi tribes that inhabited most of the Brazilian coast in the 16 th century.

Distribution, habitat, and phenology
Psyllocarpus itakangapyra sp. nov. grows on sandy and rocky soils in the "campo rupestre" vegetation (sensu Silveira et al. 2016), at ca 1300 m a.s.l. Currently it is only known from the municipality of Itacambira, in the micro-region of Grão Mogol, northern Minas Gerais (Fig. 7). However, future botanical expeditions to this region may increase the distributional range of this species. Specimens with flowers and fruits were collected in October and January.

Preliminary conservation status
Psyllocarpus itakangapyra sp. nov. does not occur within the limits of any protected area in Minas Gerais. It presents EOO and AOO equal to 1471 km 2 and 20 km 2 (kml file available as Supp. file 1). Therefore, we believe that this species would be considered endangered (EN B2abiii) in an official IUCN red list assessment, based on its EOO less than 5000 km 2 and AOO less than 500 km 2 , occurrence in five locations, and continuing decline inferred on quality of habitat due to the impacts on the "campo rupestre" vegetation, which in this case is associated with the expansion of eucalyptus plantations in the region, as noticed by us during fieldwork. Diagnosis Psyllocarpus vianae sp. nov. is similar to P. laricoides, but differs by the flowering branches determinate (vs indeterminate in P. laricoides), inflorescences in terminal glomerules (vs axillary inflorescences in 1-flowered cymes), corolla urceolate (vs infundibuliform), completely purple or the lower half of the tube white (vs tube purple and lobes light blue), tube 1.22-1.6 mm long (vs 2.9-6.7 mm long), the upper third of the lobes reflexed in mature flowers and the rest forming a false tube (vs plane to slightly reflexed in mature flowers, not forming a false tube), filaments 0.41-0.73 mm long (vs 0.2-0.4 mm long), style 0.14-0.24 mm long (vs 0.3-0.7 mm long), and seeds broadly obovate in outline (vs elliptic to broadly elliptic in outline).

Etymology
The specific epithet honours the Brazilian botanist Pedro Lage Viana, who works on the systematics of the Poaceae Barnhart with emphasis on the Bambusoideae Luerss., as well as floristic inventories in many Brazilian phytogeographic domains, but currently concentrated in the Brazilian Amazon. ʻPedrinhoʼ collected the first specimens of both species described in this paper, as he is also known to have greatly contributed to the knowledge of the flora of the Espinhaço range, especially in Minas Gerais.

Distribution, habitat, and phenology
Psyllocarpus vianae sp. nov. grows on sandy and rocky soil in the "campo rupestre" vegetation, being recorded from 1100 to 1200 m a.s.l. It is endemic to the Serra do Cabral, in the municipality of Joaquim Felício, Minas Gerais (Fig. 7). Specimens were collected with flowers and fruits on January and April.

Preliminary conservation status
Psyllocarpus vianae sp. nov. does not occur within the limits of any protected area in Minas Gerais. However, it may occur within the limits of the Parque Estadual da Serra do Cabral, a conservation unity of integral protection nearby, pending further botanical investigation in the region to evidence this record. Psyllocarpus vianae sp. nov. presents AOO equal to 4 km 2 . Therefore, we believe that this species would be considered critically endangered (CR B2abiii) in an official IUCN red list assessment, based on its AOO less than 500 km 2 (kml file available as Supp. file 2), occurrence in one location, and continuing decline inferred on quality of habitat due to the impacts on the "campo rupestre" vegetation, which in this case is also associated with the expansion of eucalyptus plantations in the region, as noticed by us during fieldwork.

Discussion
We here described two new species of Psyllocarpus, raising the diversity in the genus, as currently circumscribed, to 13 species, of which nine are classified in P. sect. Psyllocarpus. Until now, molecular phylogenetic analyses have indicated that P. sect. Psyllocarpus would appear to be monophyletic (Salas et al. 2015;Florentín et al. 2017;Miguel et al. 2018), however a comprehensive study on the genus is still lacking (Carmo et al. in. prep.).
In this section, Psyllocarpus laricoides, with which P. itakangapyra sp. nov. and P. vianae sp. nov. are closely related morphologically, appears to represent a species complex (Carmo et al. in. prep.). We recognize both entities as new species, as well as the other species in the section, based on morphological, qualitative fixed differences, which provide diagnosability ( de Queiroz 2007). Different lines of evidence may provide additional insights for the limits of these species or show otherwise, pending further investigation.
Both species described here are endemic to the "campo rupestre" of Brazil, a montane, grassy-shrubby, fire-prone vegetation mosaic associated with rocky outcrops of quartzite, sandstone, or ironstone, along with sandy, stony, and waterlogged grasslands (Silveira et al. 2016). In fact, it is an extremely old, naturally fragmented mountaintop ecosystem characterized by the staggering levels of endemism (Silveira et al. 2016). Further botanical investigation in this vegetation may reveal new species of Psyllocarpus, which might be under-represented in the Brazilian flora.