A NEW GENERIC CONCEPT 
IN THE EUPHORBIACEAE 
BY 
RicuHarp Evans ScHULTES 
AN intensive investigation of Hevea (the genus of the 
commercial rubber tree) and its nearest relatives, which 
has been in progress in the Amazon forests during the 
past ten or twelve years, has added immeasurably to our 
understanding of the composition, distribution and pos- 
sible evolutionary history of these groups. Results of this 
work have been appearing sporadically and have strength- 
ened our belief that Hevea and Micrandra are close al- 
lies,’ and may have had a more or less parallel evolution’; 
that both are related to the rather anomalous Joannesia’ ; 
and that the generic concept which had hitherto been 
known as Cunuria cannot be maintained as separate from 
Micrandra.* It is, therefore, of considerable interest that 
a new genus of the Hevea-Micrandra-Joannesia com- 
plex has now come to light. 
Vaupesia PF. FL. Schultes gen. nov. Huphorbiacearum. 
Arbores magnae, elatae, parco cum succo lacteo (vel 
‘This relationship was, apparently, first expressed by Bentham in 
1880 (in Journ. Linn. Soc. Bot. 17 (1880) 262): ‘‘Cunuria, Micran- 
dra, Hevea and Joannesia may be to a certain degree related to each 
other.’’ 
? Baldwin: in Journ. Hered. 38 (1947) 54-64; Baldwin: in Am. 
Journ. Bot. 34 (1947) 265; Baldwin and Schultes: in Bot. Mus. 
Leafl. Harvard Univ. 12 (1947) 325-326. 
*Schultes: in Bot. Mus. Leafl. Harvard Univ. 15 (1952) 201-222. 
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