Unveiling the Enigmatic Pabst and Dungs’s Promenaea rollissonii Alliance (Orchidaceae)
The enigmatic Promenaea rollissonii alliance (Orchidaceae) was established by Pabst and Dungs in 1977 and included P. lentiginosa (Lindl.) Lindl., P. riograndensis Schltr., and P. rollissonii (Lindl.) Lindl. This alliance has been taxonomically reexamined, with study of types and other collections from American and European herbaria, recent fieldwork in previously unexplored areas of the Brazilian Atlantic Forest, and observations of plants under cultivation. Promenaea rollissonii is a rare species found in particular submontane and montane Brazilian coastal habitats, and a new record extends its northern limit of distribution to Bahia State. This species is identified by the lip callus extending over the lateral lobes, and the bilobed callus at the base. The P. rollissonii alliance is recognized as the single species P. rollissonii to which the names P. lentiginosa, P. albescens Schltr., P. paranaensis Schltr. var. albescens Hoehne, and P. riograndensis newly synonymize. Neotypes are newly designated for the names P. rollissonii [≡ Maxillaria rollissonii Lindl.], P. albescens [≡ P. paranaensis var. albescens], and P. riograndensis.