Perhaps the greatest mystery in this group of plants is O. 
serpens Lindl. Lindley based his description on a single dried 
specimen without actually examining the lip for details. Since 
the type-specimen had only a single flower very nicely pressed, 
an examination of it without boiling it first, gave rise to a wrong 
description of its shape and the nature of its callus. Through the 
courtesy of Dr. Peter Taylor of the Orchid Herbarium, Royal 
Botanic Gardens, Kew, I have studied the type-specimen and | 
find it identical with O. trachycaulon Schltr. and O. Sancti- 
Pauli Kral. 
While the plants of the species mentioned above all have 
smooth peduncles without nodes which twine about branches, 
Oncidium Harlingii, a newly discovered species, exhibits a 
very different habit. The plants are epiphytic on Selaginella 
growing on the ground, its peduncles are upright and jointed. 
The species is endemic in Ecuador and its distribution is limited 
in the area of Gualaceo to General Plaza where it has been 
collected on three different occasions in association with 
Odontoglossum crinitum. 
Section Serpentia (Krzl.) Garay in Taxon 19: 455, 1970. 
Type: Oncidium serpens Lindl. 
The flowers are medium to large for the plant and range from 
2 to5cm. vertically, yellow in color with reddish brown macu- 
lations on the sepals, petals and base of lip. The sepals and 
petals are clawed, spreading; the petals somewhat wider than 
the sepals. The lip is most conspicuous, usually with small 
basal lobes; the midlobe is emarginate, transversely reniform, 
solid-colored except at the base, with a variously tuberculate 
crest. The column is short, auriculate, and thickened below the 
stigma; the rostellum is short. 
The plants are small, epiphytic, with remotely-spaced 
pseudobulbs on slender, wiry, twining or erect inflorescences. 
The mature pseudobulbs are monophyllous, rarely longer than 
3 cm., round to ovate, slightly compressed, enclosed by dis- 
tichously imbricating, leafy sheaths. The secondary inflores- 
cence is short, emerging from the axils of the sheaths, fre- 
quently from less developed pseudobulbs, usually single- 
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