46 



THE INDIA RUBBER WORLD 



[October 1. 1919. 



Hevea Confusa in Singapore. 



A TREE which has been determined as Hcvca confusa, Hemsl., 

 has been discovered in the Economic Garden of the Singa- 

 pore Botanic Gardens and recently destroyed to prevent 

 cross-pollination with seed-bearing Hcvca brasilicnsis trees near- 

 by. I. H. Burkill gives a very complete botanical description of 

 this species in "The Gardens' Bulletin, Straits Settlements," of 

 July 4, 1919, accompanied by an excellent photograph. 



The history of the tree was unrecorded, but its dark gray bark 

 attracted attention; its foliage was seen to differ from that of 

 Hevea brasilicnsis, likewise its flower. The seeds were small, 

 though not outside the extraordinarily wide limits in which 

 Hezea brasilicnsis varies. On tapping, the latex was found to be 

 yellow, meager in amount, and to remain tacky, with little 

 elasticity. 



Dried flowering specimens sent to the Royal Botanic Gardens, 

 Kew, were determined as Hciva confusa, Hemsl., by Sir David 

 Prain. Samples of the rubber submitted to Dr. Frankland Dent, 

 government analyst. Straits Settlements, and to B. J. Eaton, 

 agricultural chemist in the Department of Agriculture, contained 

 about 95 per cent of a substance chemically rubber, but lacking 

 the physical properties required in commercial rubber, proljably, 

 Mr. Eaton suggests, a polymer of caoutchouc. Rather under two 





per cent of resins was contained. The tree yielded so grudgingly 

 that the samples were too small for a vulcanization test. 



Burkill describes Hcvca confusa as belonging to the section of 

 the genus which has the male flower buds blunt rather than 



acute, as in Hcvca hiasiliensis. The female flowers are a little 

 smaller and the male flowers considerably smaller than those of 

 Hcvca brasilicnsis, but a still more striking difiference is the pose 

 of the male (lowers. The panicles arc narrower than those of 



Hcvca hrasiliciisis, as much because the angle at which the side 

 a.Kcs take off is smaller, as because they are of lesser size. The 

 weakest panicles are wholly male, as in Hevea brasilicnsis, and 

 the stronger carry more and more female flowers upon the lower 

 side branches up to S or 6. The perianth lobes are ovate and 

 blunt, and the cup extends to half their length ; they and the cup 

 are straw colored with a magenta line down the middle from the 

 tip or near it to the very base inside. Outside they are covered 

 with short hair. The top of the ovary is conspicuously blunt with 

 sessile stigmas. The male flowers are blunter than those of 

 Hcvca brasilicnsis, straw-colored, have fewer anthers, and by 

 the bending of their pedicels they face more or less earthwards. 

 Outside they are hairy. This bending of the pedicels gives a 

 very good distinguishing mark which the herbarium student 

 cannot note so well as the field student. 



Hcvca confusa originates from British Guiana. It differs as 

 little from Hcvca paiiciflora, Muell. Arg., of the same region, that 

 to unite the two on botanical eye characters is quite justified, and 

 it is not surprising that with only the seeds as a guide Dr. P. J. 

 t'ramer suggested Hevea pauciflora as the species. Hevea 

 paucitlora is known to produce hybrids of no apparent value with 

 Hcvca brasilicnsis, and that the same is true of Hevea confusa 

 is shown by the experience of planters in Trinidad. 



During the winter of 1911-1912 the Editor of The Ixdi..\ Rubber 

 World visited a plantation owned by Boston rubber manufac- 

 turers, where many confusa hvbrids were found among uue 

 Hevea brasilicnsis. The source of the seed from which these 

 trees grew was a fine thirty-year Hcvca brasilicnsis of undoubted 

 purity, growing in the Botanic Gardens of Port of Spain. About 

 one hundred feet from it was an equally large and thrifty Hcvca 

 confusa. The theory, therefore, is that bees visiting the flowers 

 of Hcvca confusa conveyed pollen to the flowers of the Hcvca 

 brasilicnsis, and thus vvfcre responsible for the creation of a 

 troublesome mongrel. That it was discovered while planting 



