Retiro near the headwaters of the Rio Igaraparana. In 
1942, I searched carefully along the I[garaparana from La 
Chorrera to its confluence with the Rio Putumayo, but 
could not find a tree showing characters similar to those 
ascribed to this species. Extensive collections of topo- 
typical material of Hevea Foau are urgently needed be- 
fore we can evaluate critically its exact relationship to HZ. 
guianensis var. lutea with which it appears to be allied.* 
* Hevea glabrescens Huber in Bol. Mus. Goeldi 
7 (1913) 230. 
Described from material gathered on the Rio Putu- 
mayo, Hevea glabrescens is rather poorly understood as 
a species. In 1942, I attempted to collect topotypical 
material, but without success. It cannot be a common 
species, for I did not find it in any locality along the 
Putumayo. Its relationships would seem to be with 
Hevea guianensis var. lutea.” Although the type was col- 
lected on the Peruvian bank of the Rio Putumayo, there 
seems little reason to believe that it does not occur on 
both sides of the river. 
Hevea guianensis 4ublet Pl. Guian. 2 (1775) 228. 
Hevea guianensis 4ub/. var. lutea (Benth.) 
Ducke et R. FE. Schultes comb. nov. 
Hevea lutea (Benth.) Mueller-Argentius in Linnaea 
34 (1865) 204. 
During several conferences which I had with Dr. 
Adolpho Ducke in Manaos in June, 1944, it became 
evident that we had arrived quite independently at the 
conclusion that Hevea lutea actually represents only a 
variety of the widely distributed and very variable HZ. 
°Ducke (Arch. Jard. Bot. Rio Janeiro 5 (1930) 152) has considered 
Hevea Foxti and H. glabrescens as varieties of H. lutea and has made 
the appropriate nomenclatorial transfers. 
[9] 
