Ypsilopus Summerh. in Kew Bull. 4: 439 (1949).
Epiphytic monopodial herbs with generally short stems, less than 15 cm long; the roots arise from the basal part of the stem. The leaves are dorso-ventrally flattened, arranged in a terminal fan or spread along the stem, linear, con-duplicate or twisted at the base to lie in one plane. The leaf-bases are distichously overlapping, leaving acute or acuminate points at each side when the leaves drop. The inflorescences are solitary, racemose, terete, spreading to suberect, arising from the axils of leaves, laxly few- to many-flowered; the peduncle and rachis are slender and terete; the bracts are amplexicaul and small. The flowers are pale green to white, with free and subsimilar sepals and petals. The lip is entire, obscurely 3-lobed, ecallose, and spurred at the base. The column is short, terete, and lacking a foot; the rostellum is truncate and dilated at the apex; the pollinia are 2 and ellipsoid; the stipes is solitary, slender, and Y-shaped; the viscidium is single, reni-form, and elliptic or oblong.
Ypsilopus comes from the ancient Greek upsilon, the letter Y, allusion to the shape of the stipes.
Type species:
Ypsilopus longifolius (Kraenzl.) Summerh.
Key to sections and species of Ypsilopus Summerh.
Epiphytes in submontane or montane forest, or in shrubby vegetation, 500-3000 m.
Kenya to S. Africa.
Bibliography and References:
Carlsward BS, Stern WL, Bytebier B. 2006 Comparative vegetative anatomy and systematics of the angraecoids (Vandeae, Orchidaceae) with an emphasis on the leafless habit. Bot. J. Linn. Soc. 151. 165-218. Pottinger M. 1982 African orchids: Plectrelminthus to Ypsilopus. Orchid Rev. 90. (1070): 384-385 (1982).; Molecular phylogeny and taxonomic synopsis of the angraecoid genus Ypsilopus (Orchidaceae, Vandeae) TAXON 68 (3) June 2019: 455–470 ; WCSP (2020). 'World Checklist of Selected Plant Families. 15.03.2017; http://apps.kew.org/wcsp/