BOTANICAL MUSEUM LEAFLETS VoL. 26, No. | 
JANUARY 31, 1978 
STUDIES IN THE GENUS ONCIDIUM — II 
SECTION SERPENTIA 
JOHN E. STACY 
As I have stated in the first paper of this series, the various 
sections of Oncidium will be handled in a random sequence, 
mostly dictated by existing needs for clarification of cultivated 
material. 
The Section Serpentia was established by Garay in 1970 in 
his review of the genus Oncidium. The group of plants compris- 
ing this section had already been brought together by Kranzlin 
in 1922 as a subsection notwithstanding the lack of any phyletic 
or genetic proximity with the rest of the Section Varicosa to 
which it was attached. 
The outstanding characteristic of this section is the remarka- 
ble habit of the plants. The inflorescences which may be com- 
pared with those of O. volvox, O. acinaceum, O. Schillera- 
num to mention a few, often develop adventitious plantlets in 
lieu of flowers. The result is a twining habit which, without 
closer scrutiny, appears to have plants situated distantly on 
thin rhizomes or stolons. The true nature of these plants was 
first recognized by Dr. Rodrigues in Costa Rica, who together 
with Dr. Daniels, give an excellent discussion on the morpho- 
logy of these plants in ORQUIDEOLOGIA 7: 79-84, 1972. 
Although the Section Serpentia contains only a handful of 
species, the individual members are still poorly known, most 
probably due to the great similarity in their vegetative growth. 
The type-species, O. globuliferum, for a long time remained 
unknown, but it is available for study now in the Paris her- 
barium. When Reichenbach first examined Humboldt’s mate- 
rial he hastily united his own O. Scansor with it. Yet both 
plants are amply distinct from one another as will be shown 
later. To make matters worse, Reichenbach described a new 
variety of O. globuliferum from Costa Rica which was indeed 
different from his concept of O. Scansor. 
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