The composition of the gum exudates from some combretum species; the botanical nomenclature and systematics of the combretaceae

An analytical study has been made of gum specimens from Combretum collinum, C. collinum subsp. hypopilinum, C. erythrophyllum, C. nigricans, C. fragrans, and C. glutinosum. In comparison with the genus Acacia, both the botanical classification and synonymy, and the chemistry, are more complex. Glucuronic acid, galacturonic acid, 4-O-methylglucuronic acid, galactose, arabinose, and rhamnose are present in all the specimens studied. In addition, mannose and xylose are present in the gum from C. collinum, which is therefore similar to C. hartmannianum. The data now available suggest that, as a group, the genus Combretum produces gum exudates that are more viscous, of higher molecular weight, and more acidic than those of the Acacia group.