There is no other known species of Hevea which com- 
bines so many exclusive and apparently anomalous char- 
acters as Hevea microphylla. The unique leathery capsule 
and its slow and gentle dehiscence (contrasting so mark- 
edly with the woody capsule and its sudden and explosive 
dehiscence in all other species) has been discussed in de- 
tail by Ducke (in Arch. Inst. Biol. Veg. 2, no. 2 (1985) 
235, 243) and by Schultes (loc. cit. 7). The peculiarity 
of this mechanism alone is enough to set Hevea micro- 
phylla entirely apart from all other species. The enor- 
mously swollen torus on the pistillate flower is likewise 
unique, for no other species of #Zevea has an analogous 
structure. The green-yellow-red coloration of the capsule 
is unknown elsewhere in the genus. Furthermore, the 
shape of the seed is completely unlike that of any other 
species, and the curious coloration is peculiar to FLevea 
microphylla. 
Huber (in Bol. Mus. Goeldi 4 (1906) 622) included 
Hevea microphylla in his series Intermediae, together 
with A. brasiliensis and H. minor, thus intimating that 
these three were more nearly allied to each other than to 
other species. Later, he suggested (in Bot. Mus. Goeldi 
7 (1918) 202) that further studies might indicate the de- 
sirability of removing Hevea microphylla and H. minor 
from series Intermediae to form, with Hl. rigidifolia, a 
new series. 
There are so many differentiating characters of the first 
magnitude to be found exclusively in Hevea microphylla 
that we are forced to regard the concept as standing en- 
tirely alone with no closely constituted allies in the genus. 
It is indeed rather puzzling. Florally, as a glance at the 
tabular summary of characters shows, AZevea microphylla 
has more characters in common with A. nitida, H. 
pauciflora and H. rigidifolia, which are probably the 
‘‘oldest’’ concepts in the genus, than with any other 
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