Bulbophyllum kiehnii and Bulbophyllum voethii (Orchidaceae), Two New Orchid Species from Madagascar

Abstract

Two new Malagasy species of Bulbophyl­lum Thouars (Orchidaceae) are described and illus­trated. Notes on conservation status, habitat, and taxon­omy are provided. An overview of taxonomic research of Bulbophyllum in Madagascar is given. Bulbophyllum voethii G. A. Fisch. & Sieder is distinct from any other known Bulbophyllum species through the combination of characters including: non-creeping rhizome; densely clustered bifoliate pseudobulbs; non-resupinated, erect, single-flowered inflorescences; a short, fully sheathed peduncle with large distinct floral bracts; sepals with one thickened vein, lateral sepals longer than dorsal sepal; pandurate lip; and a column without wings or teeth, the stelidia short and bilobed. The character set is so unique that morphologically it cannot be assigned to any existing Malagasy section. Bulbophyllum kiehnii G. A. Fisch. & Sieder belongs to section Elasmatopus Schltr. and is most similar to B. oxycalyx Schltr. It differs by having orbicular to slightly ovoid 4-angled pseudobulbs, indurate and succulent leaves, a densely multiflowered inflorescence, glabrous sepals and petals with entire margins, a strongly ligulate lip with a large adaxial callus, and a short, oblique-angled incurved and subcylindrical column foot. Based on IUCN Red List criteria, both B. kiehnii and B. voethii are provi­sionally assessed as Critically Endangered, the latter possibly extinct.