Gums, Resins. 



418 



[May 1908. 



and H. confusa, Hemsley. The true Para 

 Rubber (H. brasiliensis, Muell. Arg.) 

 does not, so far as I am aware, occur 

 within the boundaries of the colony. 

 Hevea guyanensis Aublet, the first 

 species to be described, is a native of 

 French Guiana. 



There is still a lot of confusion between 

 the different species of Hevea, and they 

 are by no means easy to discriminate, 

 without, in most cases, a careful dissec- 

 tion and examination of the flowers 

 under a magnifying glass, so that it is 

 of little use attempting to describe the 

 characters by which they can be recog- 

 nised, nor is it of much importance to be 

 able to distinguish between the three 

 British Guiana species. 



The only specimens of H. spruceana 

 we have in the Botanic Gardens Her- 

 barium, are some collected by the late 

 Mr. Jenman in 1886, on the Essequibo 

 river above Bartica. H. confusa and 

 H. pauciflora are fairly widely distri- 

 buted throughout the colony, having 

 been found at some distance up the Esse- 

 quibo, Mazaruni and Demerara rivers, 

 and there are also several trees to be 

 found scattered along the Tapacooma 

 >?reek. 



The trees are invariably found grow- 

 ing most abundantly in the lovv swampy 

 lands, fringing the sides of the smaller 

 creeks, which during the wet season are 

 subject to periodical inundations. Mr. 

 Jenman mentions that the names applied 

 to the Heveas among the various Indian 

 tribes are: Arawak, Hatti ; Carabisi, 

 Poomui ; A ckaivoi, Sibisibi, but the 

 Arawack name is the one by which the 

 trees are most generally known. The 

 trees flower from October to December, 

 and ripen their seeds in the months of 

 April to June. 



Rubber from Heveas.— Not one of the 

 British Guiana Heveas is known to yield 

 a rubber of any commercial value. The 

 samples of the 'rubber' which have 

 been collected and submitted for examin- 

 ation from time to time have all been 

 found to contain a large percentage of 

 caoutchouc. If any means can be dis- 

 covered by which the latex can be 

 caogulated into rubber with the elimi- 

 nation of the resin, it may be profitable 

 to work the trees. 



In certain parts of the colony these 

 Heveas are very numerous. In a report 

 on a visit made to the Manabadin Creek 

 on the Demerara River at the beginning 

 of the present year by Mr. R. Ward, 

 Agricultural Superintendent, in the 

 summary Mr. Ward states that he 

 found three species of Heveas in 

 this Creek, all confined to the low, 



swampy, flat lands. He says further that 

 the Creek appears to run several miles 

 inland with two tributaries a consider- 

 able distance apart from one another, 

 and that Heveas are said to be plenti- 

 ful throughout this large area. The 

 portion that he examined gave an ap- 

 proximate estimate of 200 trees to the 

 acre, with an average diameter of ten 

 inches per tree, and young seedlings 

 and medium-sized trees were common all 

 along the banks of the Creek. Mr. Ward 

 also mentions that he received infor- 

 mation of another Creek some distance 

 below Manabadin where the Heveas 

 were again plentiful. 



So that it appears desirable that the 

 whole question of the occurrence, re- 

 lative abundance, and rubber-yielding 

 capabilities of the native Heveas should 

 be thoroughly goue into, as little or 

 nothing in this direction has been done 

 since Mr. G. S. Jenman published the re- 

 port in 1883 on the " India-rubber and 

 Gutta Pericha Trees of British Guiana," 

 to which frequent reference has been 

 made in writing the above account. 



FORSTERONIA. 



In 1880, appeared another report by 

 Mr. Jenman, on " Macwarrieballi (Fors- 

 teronia gracilis). A New India-Rubber 

 Plant of British Guiana." The plant 

 was discovered near the Great Falls 

 at Mallai on the Demerara River, at 

 a distance of nearly 200 miles from 

 Georgetown. The discovery was made 

 by the accidental cutting of 'bush-rope' 

 — the general name applied to the stems 

 of all the larger creeper-* growing in 

 the forest— by a blow from a cutlass. 

 Mr. Jenman narrates that "milk immedi- 

 ately issued abundantly and dripped 

 to the ground. 1 never in any lactif er- 

 ous plant saw milk run so freely. On 

 more closely examining it I found that 

 it was also richest in rubber of any 

 such milk I had ever examined." 



With some difficulty owing to the 

 necessity of felling two or three sup- 

 porting trees, specimens of the flowers 

 of the plant were obtained, by means 

 of which the tree was identified at 

 the Kew Herbarium as Forsteronia 

 gracilis, Bth. 



Characters of Forsteronia.— There 

 are three or four species of Forsteronia 

 occurri ng in British Guiana. They are all 

 of them large-growing, climbing shrubs 

 with smooth, opposite stalked, egg- 

 shaped leaves and terminal panicles of 

 small crowded flowers. 



Forsteronia belongs to the Natural 

 Order, Apocynacece, which includes some 

 other well-known rubber-yielding plants, 



