myself must confess that it is impossible to distinguish. . . 
specimens which can positively be referred to 7. discolor, 
in spite of the fact that the leaves of many of our speci- 
mens agree much more with this species than they do with 
Hf. Spruceana, according to Mueller’s description... It 
is true that the few opened flowers of these specimens 
| Poeppig 2595, Spruce 1171] are much smaller than the 
completely developed flowers of Hevea Spruceana, but 
it seems to me that this can be due to their not having 
finished their growth. In our specimens from the lower 
Japura and Teffé, from the area of Hevea discolor, there 
is such a curious mixture of characters of HZ. discolor, 
H similis and H. Spruceana, that I have not been able 
to attribute them to one or the other species without 
reservation. At any rate, it is certain that the seeds of 
Hevea discolor from the mouth of the Rio Negro. . . 
and of HZ. similis from the lower Japura are so similar to 
those of H. Spruceana from Obidos that, if they should 
be mixed, they could not again be separated.”’ 
In summary, Huber mentioned that Hevea discolor 
must be taken from the list of trees yielding good rubber 
and be placed amongst those of no commercial value, 
together with H. Spruceana and H. similis, with which 
concepts it may one day have to be united in one single 
species. 
In his monograph of Hevea, Pax (in Engler’s Pflan- 
zenr. 4, 147 (1910)) retained HZ. discolor as a distinct 
species, placing HZ. Spruceana, H. similis and H. discolor 
together as species with obtuse staminate buds and a 
pilose under surface of the leaf. The only difference he 
noted between Hevea discolor and the other two con- 
cepts lay in the size of the staminate flowers. 
Shortly thereafter, Huber (in Bol. Mus. Goeldi 7 
(1913) 645-646, 650) accepted, apparently without hesi- 
tation, Hevea discolor as representing a distinct species, 
[ 248 ] 
