Brachystegia microphylla

Brachystegia microphylla Harms

Common names

Mountain Acacia, small-leaved Brachystegia (English); kali, kalimba, mwelela (Bemba); mukongolo (Nyanja).

General description and distinguishing characteristics

A medium-sized to large tree of up to 35 m, Brachystegia microphylla has a spreading flattened crown, which together with its feathery leaflets has earned it the common name of ‘Mountain Acacia’. This species is almost invariably associated with rocky slopes and granite kopjes, where it is often the only canopy species. It is most easily recognised by its attractive, smooth bark and small leaflets. Bark: Mottled pale grey and brown, smooth, but flaking in scales exposing rusty orange or yellow underbark. Small branchlets with ochreous rusty hairs. Leaves: Alternate compound paripinnate with 21-55 overlapping pairs of leaflets on each leaf, the middle leaflets the largest. The leaflets are linear to lanceolate, typically 0.1-0.3 x 0.7-1.5 cm, and are dark green and shiny above, paler glaucous below. The leaves appear as a salmon pink flush in October. Stipules and auricles drop early. Flowers: Produced in terminal and axillary panicles, the small greenish white flowers are themselves inconspicuous. The flowers appear at the end of the dry season around September-October. Fruit: A flattened, oblong-rhomboid pod, thinly woody, and comparatively small, rarely exceeding 10 cm in length. Produced June to September the year after flowering.

Range and habitat

Brachystegia microphylla is common along the Congo-Zambezi and Luangwa watersheds. Outside Zambia it occurs in Malawi, Mozambique, Tanzania, DR Congo and Zimbabwe. In the valley it prefers altitudes above 1000 m, but does occur in the Muchinga Escarpment at elevations as low as 800 m. It is most characteristically associated with kopjes, knolls, rocky escarpments and gorges.