and lower Rio Uaupés area, where Spruce had collected 
so extensively, for an investigation of Hevea and several 
other genera of economic plants. 
In July, 1946, in Belém, I had the pleasure of study- 
ing a number of the specimens of Hevea which Fr6es 
collected on this trip and which Dr. Adolpho Ducke had 
determined (cf. Ducke in Bol. Técn. Instit. Agron. 
Norte no. 10 (1946) 18). The scope and quality of the 
collection are such that 1 am moved to compliment the 
collector most highly on his accomplishments and Dr. 
Camargo for his part in bringing about this valuable con- 
tribution to our knowledge of Hevea in one of the most 
isolated regions of the Amazon Valley. 
Without a doubt the most outstanding achievement 
of Frées’ trip was his rediscovery of Hevea rigidifolia. 
Four excellent and extensive collections were made in 
three localities, all rather near the type locality. These 
collections greatly increase our understanding of this spe- 
cies which is certainly (with the possible exception of 
Hevea microphylla Ule (Schultes in Bot. Mus. Leafl. 
Harvard Univ. 13 (1947) 1-9) the most distinct of the 
whole genus. One of the collections includes several 
valves of the capsule and two seeds, both of which strue- 
tures have hitherto been unknown; and another collec- 
tion includes seedling material. 
In May, 1947, Fro6es recollected Hevea rigidifolia in 
sterile condition from a locality where he had found it 
two years previously. According to Senhor Froes, two 
thousand seedlings of Hevea rigidifolia from this locality 
(Serra de Tunuhy) have been established at Belterra. 
The Fro6es collections of Hevea rigidifola are impor- 
tant from several points of view. They indicate that the 
species is probably a very highly restricted endemic. It 
is evident also from a comparison of the collections with 
the type material that the species is apparently rather 
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