ABSTRACT
Within the genus Hevea (Willd.), which is well-defined, the species are difficult to differentiate and have been the subject of much confusion, disagreement, and fluctuations between authors. Except for the species H. brasiliensis, the observations have been made in often difficult field conditions and are generally quite brief. Schultes (1990) presented the most recent synthesis and distinguished ten species, of which three are subdivided into four varieties. The natural hybridizations seem limited in an undisturbed forest environment, but several interspecific morphological variations are observed. We thus speak of a species complex, according to the definition of Pemes (1984). The nine related wild species are part of the primary gene pool of the cultivated species H. brasiliensis. They are thus of great use as genetic resources of cultivated hevea, in so far as they have useful characteristics such as genetic resistance to certain diseases (Schultes, 1977, 1990).
