Abstract:

   The present paper is an attempt to make a taxonomic study of the little known

orchid genus Holcoglossum, as well as a comparison of the genus with its allies, such

as Vanda, Papilionanthe, Ascolabium, Ascocentrum, Aěrides, Neofinetia and Saccola-

bium.

     Holcoglossum was established by Schlechter in 1919 (Orchideologiae Sino-Japoni-

cae Prodromus) as a monotypic genus, based upon Saccolabium quasipinifolium Hayata.

Five years later he published another true Holcoglossum as Aěrides flavescens, which

was referred by Tang et Wang to Saccolabium in 1951.  Further investigation of this

genus was by Garay in 1972 who added two species, H. kimballiana and V. rupestris

(synonymy of Aěrides flavescens), but considered Neofinetia, a quite different taxon,

to be congeneric.  It is shown that the demarcation of Holcoglossum remains cofused.

During the course of our study, the species of Holcoglossum and its allied genera are

carefully examined, we come to the conclusion that Ho lcoglossum is a distinct genus.

It is characterized by the short stem; fleshy terete or subterete, sulcate above leaves,

with their apex acute and non-lobed; thickening or keeled costa on the back of sepals,

3-lobed lip, with erect sidelobes, paralled to the column; slender and recurved spur;

footless column usually with prominent wings; 2 notched pollinia attached to linear

stipe which is tapered toward the base.  In addition to Ascolabium, it differs from

Vanda, Papilionanthe, Ascocentrum, Aěrides, Neofinetia and Saccolabium by its terete

or subterete leaves on their ventral side with a furrow, from Papilionanthe by lacking

footless column, from Ascolabium by sepals and spur characters, from Ascocentrum by

slender and recurred spur, from Aěrides by the absence of a column-foot and the

appearance of spur, from Neofinetia by stipe tapered toward the base, from Saccolabi-

um by both aspects of the vegetative organs and the flowers.