Notes

This is a complex species which includes a number of more or less recognizable forms. Variability abounds in the growth form and habit. There are delicate erect annual forms, with weak roots, in which the cotyledons are persistent. These annuals have often relatively small flowers and fruits. Later on they may develop a climbing habit, becoming biennial or perennial. Coarse perennial forms are found mostly in mountainous areas (Usambara Mts.), and. have a thick perennial rootstock. Often the flowers are variable in size in a single specimen, apparently partly in relation to their age. The indumentum varies as much. Glabrous forms are probably most common, but glabrescent or hairy forms are frequent as well; hairy specimens occur apparently only in the perennial forms. A few specimens (Greenway & Kanuri 11271, 11883, Makin 14036 and Gillett 19182) are remarkably scabrous. Leaf shape and texture is very variable. Unlobed leaves are rarely found.A few specimens, viz. Haerdi 385/0, Schlieben 1577 and 2078, all from Ulanga District in Tanzania (T6), have some characters in common with B. hanningtoniana and 6, B. lanceolata, as well as with 4, B. zanzibarica. All have unlobed leaves, with distinct unwinged petioles with a few slender gland-teeth near the top. A toothed petiole is characteristic of certain forms of B. lanceolata. In habit the three specimens resemble B. zanzibarica, but the flowers are petalous; Schlieben 1577 has 5 or 6 sepals and petals, Schlieben 2078 has 4 or 5. Haerdi 385/0 has the normal 5 sepals and petals, but is in habit and nearly all other characters identical with Semsei 1327, a specimen without petals and doubtlessly belonging to 4, B. zanzibarica.  As in certain other annual species, sometimes large elliptic cotyledons are still present in full-grown annual specimens. In some annual forms bracts in the inflorescences are absent.