variations, even for such a variable genus as Hevea. That 
Pax, who had never had an opportunity of studying this 
rubber tree in the field, created var. major should not be 
too strongly decried, for without a large series of speci- 
mens or some field work, such variation really would 
seem to be significant. 
There is occasionally some variation in the texture of 
the leaflets. Sometimes one finds a deviation from the 
stifHy papyraceous texture and an approach to what we 
may term almost subcoriaceousness. This, | have ascer- 
tained in the field, is due neither to the age of the leaf- 
lets, nor to seasonal changes in the tree, nor to ecological 
factors. It might possibly be interpreted as an indication 
of hybridization, but after extensive association with 
Hevea microphylla in the field, I believe that, in general, 
there has been comparatively little hybridization of 
Hevea microphylla with other species. 
Hevea microphylla customarily has subconcolorous 
leaves, although often they dry markedly discolorous, a 
phenomenon which prompted my statement, in separat- 
ing the concept known as Hevea minor from H. micro- 
phylla (Schultes, loc. cit. 8) that A. microphylla is charac- 
terized by ‘‘folia discolora.’” There are, however, devia- 
tions from this subconcolorous condition. Schultes & 
Lopez 9691, pointed out above as being atypical as to 
size and shape of leaflets, is also noteworthy in being 
rather subcoriaceous with the two surfaces, in life, differ- 
ing markedly in color; the upper a dark, glossy green; 
the lower, a very pale, dull green. It might be argued 
that this tree had genic influence from Hevea pauciflora 
var. coriacea, but since other characters appear to be nor- 
mal and the habitat was a more or less open swamp with 
no shade, this texture might as logically be the result 
of adaptation for extreme xerophytism and radiation. 
In the length of the petiole, there is hardly any vari- 
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