| 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 Saccolabium.
Holcoglossum was established by Schlechter in 1919 (Orchideologiae Sino-Japonicae 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. |
