Tab. 6322. 
ONCIDIUM Euxanthinum. 
Native of Brazil. 
Nat. Ord. Orchide^:. — Tribe Vandeye. 
Genus Oncidium, Sivartz, ( Lindl . Fol. Orchid. Oncidiam). 
Oncidium (Micropetala) euxanthinum ; pseudobulbis ellipsoideis compressis canali- 
culatis, foliis binis lineari-ensiformibus acutis acute carinatis, panicula 
amplaramosa, bracteis triangulari-subulatis, floribus 1-poll. diam. aureis disco 
rubro-maculato, sepalo dorsali columna vix longiore cucullata, lateralibus 
parvis acutis connatis, petalis paulo longioribus oblongis obtusis undulatis, 
labelli trilobi ungue brevi porrecto lobis lateralibus sessilibus rotundatis 
crenatis intermedio maximo subreniforme bilobo sinu acuto, callo inter lobos 
antice multilobulato, postice in cornu porrecto, columna brevi alis lobulatis. 
O. Euxanthinum, Reichb.f in Oard. Ohron. 1869, p. 1158. 
A member of a small group of chiefly Brazilian Oncidia, of 
which the first described species is 0. Ufolium , Sims, (Tab. 
nostr. 1491), a native of the Brazils, which differs in the 
racemose flowers, much smaller broadly obovoid pseudo -bulbs, 
and shorter leaves. It is even nearer the 0. martianum var. 
bicolor , Lindl. (0. bicolor , Lindl. in Bot. Beg. 1847, t. 66) in 
the racemose flowers, but that species has a solitary broad 
leaf, and very much narrower lateral lobes of the lip. Dr. 
Beichenbach, who has kindly verified the name for me, de- 
scribes the flowers of the original specimen as having greenish 
sepals and petals with brownish bars, but those of the speci- 
men here figured are of the same clear yellow as the lip, and 
the spots on the latter are of a clear red hue. The warts etc. 
of the lip are not only variable in this genus, but most diffi- 
cult to describe ; in the present species they occupy a narrow 
area on the disk, and consist principally of a transverse row of 
tubercles and a prominent but small conical horn. 
0. euxanthinum is a native of Brazil, whence it was im- 
OCTOBER 1st, 1877. 
