REPORT ON THE CAOUTCHOUC OF COMMERCE. 
5 
Mara] 6 to its source. Also its tributaries, the Tocantins, 
the chief Para district being between it, and the Zingu, 
along and between the Tapajoz and Madeira from 3° to 
7° S. lat. On the Eio Negro, Casiquaiari and [Taupe s. 
They also occur, according to Dr. Weddell, plentifully 
on the plains cf the Orinoco.* 
Of the species above enumerated, Dr. Spruce remarks (in letter to 
Collins) Caoutchouc is obtained : 
At Para, from Siphonia JBrasiliemis , Willd., and probably from 
several other species of the same genus : 
On the Amazon. About the mouth of the Tapajoz, from S. 
Spruceana , Benth. ; towards the mouth of the Madeira are other 
species not seen by him in good state : 
On the Eio Negro, Uaupes, and Casiquiari, from — 
S. discolor , Spruce ; 
rigidifolia ) Spruce ; 
S. lutea , Spruce; 
S. paucifolia , Spruce ; 
S. apiculata, Spruce, 
and from two other species (Nos. 3326 and 3457). 
Micrcmdra minor , Benth., L c., D. C. Prod,, vol. xv., p. 709, et 
Jf. siphmioides , Benth., 1. c., D, C. Prod., 1. c. 
Geographic Distribution. — Eio Negro. 
Eemarks, — On the Eio Negro, Caoutchouc, elastic as that 
of the . Seringas, is obtained from this genus (Spruce). 
Dr. Spruce mentions another genus near Hevea* called by the 
Barre Indians Ounuri , whose sap contains Caoutchouc, and from 
whose seeds a vegetable butter is prepared. 
Climatic Conditions of the IIeveal 
Para District. — In Para the seasons are modified, as to be almost 
exceptional. Guiana and Brazil to the N. and S. of the Para 
district forms a somewhat elevated tableland, whilst between them 
is the Para district, the river- valley of which forms a wide extent of 
low-lying country. During six months very little rain falls (August 
to February), the heaviest rains being in April, May, and June. 
Mr. Wallace gives the rainfall for 1847 as 15 inches in April, being 
the greatest monthly rainfall for that year. In January, Feb- 
* Mr. II. A. Wickham (“Rough Notes of a journey through the Wilderness from 
Trinidad to Para, &c.,” London, 1872) noticed fine “ Ciringa” trees on the banks of 
the Orinoco, and collected caoutchouc for commercial purposes on an island in the 
River Caricia or Chirari. 
