Studies in the GenusHevea. VIII. Notes on infraspecific variants ofHevea brasiliensis (Euphorbiaceae)

Supplying 98% of the world's natural rubber,Hevea brasiliensis has transformed life around the world in only a century. This species-one of 10 in its genus-gives the best natural rubber, but much more remains to be studied concerning the numerous localised strains of the species. The British introduced to the Orient seeds from the lower Amazon-representatives of a not superior ecotype of the species but, at that time a century ago, the only available germ plasm. The time for study of the intraspecific variants ofH. brasiliensis and their use in programmes of genetic manipulation of the genus is long overdue. But basic to this desired programme is a clear taxonomic understanding of infraspecific variants, still awaiting evaluation. Although numerous taxonomic treatments of subspecific variants have been offered, there is little available to give genetic programmes concrete information.