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The Chapada dos Veadeiros National Park is a conservation unit established to preserve the highest savannahs of Central Brazil and their unique biodiversity. Eriocaulaceae are a relevant and conspicuous family in such high savannahs, but its diversity is poorly known, documented solely in general lists or in isolated efforts aimed at small groups. After a structured series of field expeditions and analysis of specimens from the relevant herbaria, we provide nomenclatural novelties, a first identification key, and an illustrated checklist for the species of Paepalanthoideae (Eriocaulaceae) in the area. We recorded 42 species of Paepalanthoideae from the Chapada dos Veadeiros National Park: Actinocephalus (Körn.) Sano (2 spp.), Comanthera L.B.Sm. (1 sp.), Paepalanthus Mart. (24 spp.), and Syngonanthus Ruhland (15 spp.). Actinocephalus brevifolius Trovó & Echtern. sp. nov. and P. irwinii Trovó & Echtern. sp. nov. are newly described species and P. politus Trovó stat. et nom. nov. is a variety of P. elongatus (Bong.) Körn. raised to the species status with a new name. The generic and specific composition shows predominance of Paepalanthus and Syngonanthus, and with a low representation of Actinocephalus and Comanthera, as expected, outside of the Espinhaço Range. More than 50% of the species (22 spp.) are endemic to the area and 25 species are endemic to Central Brazil, the area being the main center of diversity for dimerous-flowered groups. The non-endemic diversity is a combination of widespread species and marginal distribution of species typical from the Amazon and southeastern savannahs. The species are unevenly distributed in the area, with their occurrence correlated to altitude, water availability, and lithology. We reinforce that the savannahs from Central Brazil are a secondary center of diversity for Eriocaulaceae, playing a central role in the conservation of an unique and irreplaceable piece of its diversity and the Cerrado biome as well.
Habenaria karstica J.A.N.Bat. sp. nov., a new species from limestone outcrops (i.e., karst) in the State of Minas Gerais, Brazil, is described. The new species is ecologically very distinct since it is the only Neotropical species of the genus that grows on limestone outcrops under full sun, associated with mat-forming saxicolous plants. It is morphologically similar to species of the Habenaria repens complex, and separation is only possible through a combination of morphological characters. Bayesian and parsimony phylogenetic analyses based on nuclear (rDNA ITS, ETS) and plastid (matK-trnK, rps16-trnK) DNA markers revealed that H. karstica belongs to H. sect. Spathaceae. The new species, however, differs in floral morphology from the other species in this clade. A survey of the literature and public plants datasets revealed 122 species and 58 genera of Orchidaceae in karsts of Brazil. Although small compared to the family’s diversity in the country, Orchidaceae is among the families with the highest number of species in some karst localities. Our results indicate that approximately 97% of Orchidaceae found in karsts of Brazil is not limited to limestone outcrops areas, and that species composition of each locality is primarily determined by the regional flora and the biome in which it is located.