November, 1911.] 



389 



Saps and Exudations. 



It is as follows : " In a copy of a paper 

 I have just received through the kind- 

 ness of Monsieur J. Huber, of the Para 

 Museum, entitled ' Revue Critique des 

 Especes du genre Sapium,' I observe t hat 

 our specimens identified as Sapium 

 aucuparium, Jacq., have been referred 

 to a new species 5". Helmsleyamim 

 Huber." Now Mr. Bartlett quotes Dr. 

 Huber as writing of Para rubber as 

 follows: "Little of it (Para rubber) is 

 pure Hevea rubber,but usually a mixture 

 of the latices of H. braziliensis and 

 Sapium aucuparium. The rubber of 

 (S. aucuparium has never been marked 

 alone, and very little can be said 

 definitely of its value. But when mixed 

 with Hevea latex a rubber is produced 

 not to be distinguished from the sup- 

 posed pure Hevea rubber." 



Mr. Bartlett brought forward two 

 theories, in 1907, to reconcile these 

 different experiences as to the latex of 

 the so-called local <!■?. aucuparium, viz. , 

 either that the species wa,s different, or 

 to quote this authority " more than one 

 distinct species have been included 

 under this name." or that the trees yield- 

 ing resin in this colony on our coastlands 

 were only comparatively young trees. 



It is a well-known fact, of course, 

 that if we except Hevea brasiliensis, 

 many rubber-producing trees yield, 

 when they are young, poor quality 

 resins rather than caoutchouc. 



At any rate sufficient has been said 

 to show that it is important that there 

 should be no confusion concerning the 

 identity of this tree. 



But the question of the resinous 

 quality of the latex furnished by trees 

 known to yield rubber of good quality 

 when they have attained a number of 

 years, brings us to that which natur- 

 ally is now arising. Do the so-called 

 & Jenmani yield rubber at a sufficiently 

 early stage of growth to make planting 

 Sapium rubber-growing a commercial 

 undertaking ? Have we to wait for five 

 or fifty years before a product com- 

 paratively rich in rubber and poor in 

 resin is obtained ? These are questions 

 which we should very much like to see 

 definitely settled, while the provoking 

 variability of the genus itself also pleads 

 for a nomenclature, the definiteness of 

 which may give the answer to many 

 puzzling conditions. 



As its available characteristics, I may 

 mention that, recently in the North- 

 Western District, I found a Sapium sp, 

 with a twisting, tortuous stem, which 

 was hugging in its vice-like grip one of 

 our native palm3, in an embrace which 

 must prove to be one of death, so far 

 as the unfortunate palm is concerned. 



One would have been certain that 

 this cruel habit belonged to a native 

 Ficus, but the leaves proved the tree 

 to be a Sapium, and one which yielded 

 a thick-creamy latex apparently rich 

 in caoutchouc and quite different from 

 the sticky substance furnished by our 

 Ficus and non-rubber yielding Sapiums. 



To return to the question of the 

 mixing of latices of S. aucuparium and 

 Hevea brasiliensis, it might prove of 

 interest to carry out some experiments 

 with the mixing of the latex of Sapium 

 Jenmani and other rubber-yielding 

 Sapiums with that of Hevea brasiliensis. 



Quite recently the writer was told 

 of a case where the latex of Hevea 

 brasiliensis was mixed with the thick 

 yellowish latex of one of our indigenous 

 Heveas, (possibly H. cnnfusa), with the 

 result that the product was very 

 favourably reported on it* England. 



In the Aruka valley of the North- 

 western District the conditions are 

 exceptionally suited to Sapium growing. 

 There the tree makes most amazing 

 growth on the soft pegassy lands of the 

 district. On the other hand this peat 

 soil does not support Hevea brasiliensis 

 satisfactorily, though where it is mixed 

 with the clay sub-soils the growth of 

 this tree is fair, such as on the dams 

 that have bean thrown up when trench 

 digging operations have been carried 

 out. On the heavy clays of the coast- 

 lands rubber-yielding Sapiums are, 

 apparently, a failure. They are attack- 

 ed by scale ( Lecanium chiefly) and make 

 poor and stunted growth. 



A noticeable characteristic of some of 

 our Sapiums, frequently even in the 

 case of trees growing in the iuterior, is 

 the dying back of the topmost branches. 



As to the product, it has been proved 

 that some of our wild Sapium trees 

 yield a rubber which can command a 

 price, when cleauly prepared, very 

 little below fine hard Para. 



In the North-Western District consi- 

 derable progress has been made with the 

 planting of Sapium trees, this activity 

 being due chiefly to the pioneer efforts 

 of the late Mr. David Young. As the 

 trees planted by Mr. Young must have, 

 in many instances, attained some six 

 years, possibly we shall be shortly in a 

 position to know something definite 

 concerning the yields and the quality 

 of the product obtained from trees at 

 an age when Para rubber is tappable. 



Until information as to the yield 

 and quality obtained from cultivated 

 Sapiums is forthcoming, there does not 

 appear to be much probability of many 

 more estates undertaking any such 

 cultivation extensively. 



