Canarium sect. Africanarium nov. sect. (Burseraceae)

In my revision of the genus Canarium (Blumea 9, 1959, p. 275—475), C. schweinfurthii was included in sect. Canarium and within this section in the denticulatum-group (see p. 382). The main arguments for giving it that position were: 1. its general resemblance in several characters with sect. Canarium, more specially the apparent morphological equality of its stipules, a key character in the genus; 2. its apparent relationship to C. madagascariense Engl. the inclusion of which in the denticulatum-group is beyond any doubt, and, 3., its geographical position at the end of the chain of species forming the denticulatum-group — from W. Malesia to E. Africa, C. schweinfurthii being restricted to W. and Central Africa — without any connection to other groups of the genus (sect. Pimela does not go farther to the west than the Malabar coast of India). Still, it was not without doubt that I put it into this position. I expressed my doubts most clearly on p. 314—315, pointing to the presence on the one hand of some apparently primitive characters — in fact more primitive than could be expected in case of a direct derivation from the western chain of species of the denticulatum-group — as e.g. the axillary inflorescence and the presence of a rather strongly developed pistillode in the ♂ flower, of some doubtless highly evolved characters on the other hand, like the deeply concave receptacle in the ♀ flower and the ‘androphore’ in the ♂ one. Hence I concluded that the species ‘must have been isolated for a very long time’. Recently, morphological and blastogenetical studies brought new evidence as to the systematical position of C. schweinfurthii. From both it became quite clear, that the ‘stipules’ are not at all comparable with those of sect. Canarium, but are homologous with the pseudo-stipules of sect. Pimela; there is no doubt that they are derived from a pair of leaflets. The germination, however, which seems to provide good characters on sectional level in Canarium, differed from both sect. Canarium and sect. Pimela: the cotyledons were herbaceous long-lasting assimilating-organs like in sect. Pimela, but the first two leaves formed a pair of opposite pseudo-cotyledons like in sect. Canarium, and the restingperiod came after the unfolding of the latter two, also like in sect. Canarium. A more detailed discussion of these morphological points will be given elsewhere (Weberling & Leenhouts, in press).