Tackling the Paepalanthus elongatus complex (Eriocaulaceae) in central Brazil: nomenclatural changes and description of a new species from Goiás

Abstract

In Paepalanthus ser. Dimeri, one of the few groups of Eriocaulaceae with dimerous flowers, the poorly understood circumscription of Paepalanthus elongatus and its numerous infraspecific taxa challenge the delimitation of the remaining taxa and distorts the group’s actual diversity. In order to clarify the taxonomy of the group in central Brazil, nomenclatural and taxonomic changes are proposed. Paepalanthus cassiae is described based on specimens usually misidentified as P. elongatus, as well as specimens collected on recent field trips. The new species is easily distinguished from P. elongatus by its smaller habit, dark castaneous leaf sheath, and golden to pale straw-colored involucral bracts, twice as long as the floral disc. Paepalanthus longibracteatus and P. niger are raised to species status based on P. elongatus varieties briefly described by Harold Moldenke. Detailed descriptions are provided for these species. The three species detailed occur in the vicinities of the recently extended Chapada dos Veadeiros National Park. Details of the species’ etymology, distribution, biology, conservation status, and morphological variation, along with illustrative photographs, are provided. Paepalanthus elongatus var. glabrescens is treated as a new synonym of P. elongatus var. elongatus.

The Paepalanthoideae (Eriocaulaceae) of the Chapada dos Veadeiros National Park, Brazil: taxonomic novelties, identification key, and illustrated list of species

“…glabrescens based on a single collection (G. Hatschbach 36772), distinguished from the typical variety solely by its narrow leaves and glabrous or subglabrous spathes. Trovó (2018) considered such character states as within the morphological variation of Paepalanthus elongatus var. elongatus and proposed its synonymization.…”

“…elongatus and proposed its synonymization. Trovó (2018) also commented that two isotypes (G. Hatschbach 36772 MO, UPCB) were annotated by Moldenke himself in 1975 as Paepalanthus elongatus var. angustifolius Silveira, enhancing the fragile delimitation of such taxa.…”

“…Diphyomene, and P. ser. Dimeri (Trovó et al 2013(Trovó et al , 2015a(Trovó et al , 2017(Trovó et al , 2020Trovó 2018;. Interestingly, the only recorded Comanthera is dimerous and endemic to Chapada dos Veadeiros (Echternacht et al 2015).…”

“…The diversity of Eriocaulaceae in Central Brazil is also relevant as the family is a frequent floristic element in the high rocky savannahs in this region. The diversity is, however, poorly known, being documented in general lists or isolated efforts focused on small groups (Munhoz & Felfili 2006;Trovó et al 2013;Trovó 2018). New taxa published in the last decade point to the high potential of the area for taxonomic novelties (e.g., Echternacht et al 2015;Trovó et al 2015aTrovó et al , 2017Trovó 2018;Watanabe et al 2015aWatanabe et al , 2015bWatanabe et al , 2016.…”