agated from budwood. When I saw Hevea microphylla 
at Belterra in September 1948, it appeared to me to show 
rather slow growth as compared with Hl. Benthamiana 
and HI. Spruceana which had been introduced from the 
same general area and which occur naturally in sites 
which are ecologically similar to those occupied by A. 
microphylla. At Belterra, of course, the material was 
budded on root-stocks, presumably of Hevea brasiliensis, 
growing on a high, well-drained plateau. 
The recent trips of Senhor Ricardo de Lemos Fr6es 
to the Rio Negro have extended our knowledge of the 
range of Hevea microphylla. Several of his collections, 
cited below, are referable to this concept. Irdes 872, 
collected in 1942, is stated to have been found in the 
‘‘middle Rio Negro, 600 miles... from Manaos’” and 
Froes 812B in the Rio Enuixi, in the Municipality of 
Sio Gabriel, much farther upstream, near ‘Tapurucuara. 
In 1947 and 1948, Fr6es secured material from the Rio 
Padauari and the Rio Caurés, interesting affluents of the 
middle course of the Rio Negro. 
In 1944, Dr. John T. Baldwin, Jr., who carried out 
cytogeographic studies of Hevea in the Amazon Valley, 
visited the Rio Negro. In an article on his interpretation 
of the genus Hevea (in Journ. Hered. 88 (1947) 54), he 
reported: ‘‘HZ. minor was found on the Rio Uaupés as 
a bottle-butted tree, at the Venezuelan border, as a tree- 
let to 10 feet, and along the Rio Negro in estradas with 
AH. Benthamiana and of stature comparable to that of 
representatives of HT. Benthamiana.”*> Specimens of 
Baldwin’s collections have been unavailable to me for 
study, but in conversation Baldwin has assured me that 
the tree to which he was referring in this statement 
represents the concept now known correctly as Hevea 
microphylla, 
In October 1947, in company with Ing. Agron. Joao 
[114 ] 
