Sobralia rosea Poeppig & Endlicher Nov. Gen. ac 
Sp. 1 (18386) 4, t 98, 
Schultes 3559 is the second collection from southern 
Colombia of this orchid which is widespread on the east- 
ern slopes of the Andes. 
Cotompra: Comisaria del Putumayo, Rio San Miguel 6 Sucumbios, 
Santa Rosa y alrededores. ‘‘Flowers white, tip of column purple. 
Kofin Indian name: ku-pu-fii-mem-ba. April 7-8, 1942, Richard 
Evans Schultes 3559. 
Xylobium squalens (Lindl.) Lindley var. gracile 
(Schitr.) C. Schweinfurth in Bot. Mus. Leafl. Harvard 
Univ. 11 (1944) 198. 
This is apparently the first collection from Colombia 
of Xylobium squalens var. gracile, hitherto known only 
from Ecuador. 
Cotompra: Comisaria del Putumayo, Paramo de Tambillo, nordeste 
del Valle de Sibundoy. “‘Flowers cream with red specks.’’ December 
13-14, 1942, Richard Evans Schultes & C. Earle Smith 3094. 
MorackEakE 
Perebea lecithogalacta (R. EL. Schultes) R. EL. 
Schultes comb. nov. 
Castilla Ulei W arb. forma lecithogalacta R. E. Schultes 
in Bot. Mus. Leafl. Harvard Univ. 12 (1946) 128. 
Further investigation has indicated that this concept, 
which was referred to Castilla Ulei as a form, represents 
a new species of the related genus Perebea. 
The genus Perebea has hitherto not been considered 
as a commercial source of rubber, but P. /ecithogalacta 
is felled indiscriminately with Castilla Ulei in the upper 
reaches of the Vaupés River in Colombia for the produc- 
tion of ‘‘caucho negro.”’ The latex, when it flows from 
the wound, is first a deep cream color but rapidly becomes 
a bright canary yellow. 
It is evident that the 
‘ 3 
‘caucho negro”’’ of this area of 
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