BURMANNIACEAE 
Gymnosiphon cornutus (Benth.) Bentham & 
Hooker filius Gen. Pl. 8 (1888) 458. 
The collection cited below establishes the occurrence 
of Gymnosiphon cornutus in the Colombian Amazonas. 
This species is much rarer in herbaria and is apparently 
much more restricted in its distribution than the closely 
related Gymnosiphon tenellus (Benth.) Urban which oc- 
curs from Guatemala to Brazil. 
Cotoms1aA: Amazonas, Loretoyacu River, Lake Pichuna, pale bluish 
white root-parasite found with Triuris and Leiphaimos, November 
1944, R. EB. Schultes 6180 A. 
CACTACEAE 
Mediocactus megalanthus (Schum.) Britton & 
Rose Cactaceae 2 (1920) 212, fig. 292. 
The occurrence of this beautiful epiphytic cactus 
within the boundaries of Colombia is established by the 
collection Schultes 5811. Croizat (Caldasia 9 (1944) 350) 
had previously included it in an enumeration of cacti 
which were to be expected in Colombia. The type was 
collected at T'arapoto, Peru, far from the Vaupés. 
Mediocactus megalanthus is said to have the largest 
flowers of any of the Cactaceae. 
Cotomsia: Vaupés, extensive vine-like epiphyte. Leaves triangular 
in cross section, ash-grey with very small spines. Joints 3-4 feet long. 
Flower large and showy. Petals white, sepals light brownish red and 
yellowish. Pedicel reddish green, fleshy with red-tipped bracts, each 
with a small spine in the axil. Hanging on gigantic trees. Rio Vaupés, 
5 kilometers above Cerro Cireasia, March 4, 1944, R. E. Schultes 5811. 
EUPHORBIACEAE 
Hevea viridis Huber var. toxicodendroides 
R. E. Schultes & EH. L. Vinton in Caldasia 11 (July, 
1944) 25. 
[ 123 J 
