THE HEVEA RUBBER TREE IN THE AMAZON VALLEY 
point continued up the Madre de Dios to Sena. When the party 
returned by. river and rail to Abuna at the mouth of the river of that 
name a division of the party was made; the Brazilian and Commerce 
parties ascended the Abuna into the Acre Territory and crossed 
overland to the Rio Acre, while the Agriculture party came back to 
the Andird at Porto Velho and returned on that boat to Manaos and 
later to Para. 
At Para Doctor Weir was transferred from the rubber investiga- 
tions to other work and proceeded to Rio de Janeiro and Buenos 
Aires before returning to New York. Prizer and Jessup returned 
to Washington, while the writer sailed for Cobija, in the Acre Terri- 
tory of Bolivia, by way of the Amazon, Purus, and Acre Rivers. The 
return journey was made over the same route. 
THE GENUS HEVEA 
Mention has already been made of the fact that La Condamine 
(13) was the first scientist to take note of the rubber tree and its 
strange product and that he published (14) the description and 
drawings of a Hevea. tree submitted to him by Fresneau, which are 
the earliest extant. It is most likely that the rubber which La 
Condamine first saw in the Province of Esmeraldas did not come 
from a tree of Hevea but from some species of Castilla, but Fresneau's 
drawings and descriptions, imperfect as they are, undoubtedly refer 
to some species of Hevea. 
Fusee Aublet (4) in 1775 established the genus Hevea with Hevea 
guianensis as the type species. The name "Hevea" he derived from 
Heve, which he says is the Carib name for the tree. Plate 335 of 
Aublet's work is labeled Hevea peruviana for some reason, but is 
really H. guianensis. 
Since the time of Aublet certain species of the genus have been 
known by a number of different generic names, such as Siphonia, 
Caoutschoua, Siphonanthus, Jatropha, and Micrandra; but Hevea 
has finally been firmly established as the proper generic designation. 
Spruce (41) in his long sojourn on the Amazon assembled a con- 
siderable number of species of Hevea, among which are found Hevea 
spruceana Muell. Arg., H. discolor Muell. Arg., H. membranacea 
Muell. Arg., H. pauciflora Muell. Arg., H. rigidifolia Muell. Arg., 
H. benthamiana Muell. Arg., H. lutea Muell. Arg., and H. brasiliensis 
Muell. Arg. 
Martius (27) and Richard Schomburgk (36) also collected species 
of this genus; in more recent times Ule (42), Huber (9, 10, 11), and 
Ducke have been active in this work. 
In 1873-74 volume 11 of Flora Brasiliensis by Martius (27) ap- 
peared, consisting of the Euphorbiacese treated by Mueller Argo- 
viensis. In this the following 11 species of Hevea were recognized: 
Hevea spruceana Muell. Arg. 
Siphonia spruceana Benth. 
H. discolor Muell. Arg. 
Micrandra ternata R. Brown. 
Siphonia discolor Benth. 
H. membranacea Muell. Arg. 
H. pauciflora Muell. Arg. 
Siphonia pauciflora Benth. 
H. rigidifolia Muell. Arg. 
Siphonia rigidifolia Benth. 
H. nitida Muell. Arg. 
H. benthamiana Muell. Arg. 
H. lutea Muell. Arg. 
Siphonia lutea Benth. 
H. brasiliensis Muell. Arg. 
Siphonia brasiliensis Kunth. 
H. janeirensis Muell. Arg. 
H. guianensis Aubl. 
Jatropha elastica Linn. 
Siphonia elastica Pers. 
Siphonia cahuchu Willd. 
