bian frontier as to suggest the probability of its occur- 
rence within the boundaries of this country. 
Hevea Benthamiana Mueller-Argentius 
Hevea brasiliensis (H}BK.) Muell.-Arg. var. subconcolor Ducke 
Hevea Foxii Huber 
*Hevea glabrescens Huber 
Hevea guianensis Aublet 
Hevea guianensis Aub/. var. lutea (Benth.) Ducke & R. E. Schultes 
Hevea pauciflora (Spruce ex Benth.) Muell.-Arg. var. coriacea Ducke 
*Hevea rigidifolia (Benth.) Mueller-Argentius 
Hevea viridis Huber 
Hevea viridis Huber var. toxicodendroides R. FE. Schultes & E. L. 
Vinton 
Hevea Benthamiana Mueller-Argentius in Lin- 
naea 34 (1865) 204. 
Hevea Benthamiana is usually found in those swampy 
regions commonly known as ‘‘rebalsés’” or ‘‘igapdés,”’ 
areas which are subjected to heavy yearly inundations 
during the rainy seasons and which are more or less per- 
manently boggy. This species is often closely associated 
with Hevea viridis and H. pauciflora var. coriacea, often 
hybridizing with the latter and possibly also to a lesser 
extent with the former.‘ 
Frequently, this species is seen in association with the 
interesting ‘‘moriche”’ or ‘‘canangucho”’ palm (Mauritia 
minor), one of the most striking indicators of igap6 areas. 
Because of its predilection for moist and acidic habitats, 
Hevea Benthamiana generally occurs close to and along 
the banks of rivers and creeks (especially those which 
carry little suspended clay or sand and which are known 
as ‘‘aguas negras’’), rarely invading the usually higher 
hinterland. This species has no special common name in 
‘he most extensive hybridization of Hevea which I have seen in 
Colombian forests is that of Hevea Benthamiana © H. pauciflora var. 
coriacea in the Rio Miritiparana above the Raudal de Chimborazo where 
there are stands of the hybrid and of the two parents. 
[6 ] 
