Brachylaena is a genus of trees and shrubs in the family Asteraceae (the daisy or composite family), order Asterales. The genus comprises roughly a dozen species distributed across sub-Saharan Africa, with several species endemic to Madagascar and the remainder found on mainland Africa, particularly in southern and eastern regions.
Plants in the genus are woody — ranging from large shrubs to towering trees — with leaves arranged alternately along the stems. They are dioecious, meaning male and female flowers occur on separate individuals. The flower heads are somewhat disc-shaped; heads bearing female flowers are larger and produce larger pappi (the feathery or bristly structures that aid seed dispersal, characteristic of the Asteraceae).
Brachylaena includes some of the tallest members of the entire daisy family. Brachylaena merana, endemic to Madagascar, can reach up to 40 m (130 ft), making it one of the tallest composites known. Brachylaena huillensis of East Africa reaches similar heights and is the most ecologically prominent species in the genus: it is the only widespread member, growing as a dominant tree in so-called Brachylaena woodlands and as a frequent component of eastern African forest. It provides critical habitat for numerous animal species. Its valuable timber, however, has led to overexploitation, making it a species of conservation concern across parts of its range.
Distribution
Brachylaena is distributed across sub-Saharan Africa, with several species endemic to Madagascar and the rest occurring on the African mainland, especially in southern and eastern Africa. Brachylaena huillensis is the only species with a broad range, growing across eastern African forests and woodlands.
Ecology
Brachylaena huillensis is an ecologically dominant tree across parts of eastern Africa, forming distinct Brachylaena woodlands and occurring commonly in mixed forest. It provides critical habitat for many animal species. The wood of this species is highly valued and the species has been significantly overexploited across parts of its range.
Taxonomy Notes
The taxonomy of some species is contested. Brachylaena rotundata S.Moore is treated by some authorities as B. discolor var. rotundata (S.Moore) Beentje, and B. transvaalensis Hutch. ex E.Phillips & Schweick. is considered a synonym of B. discolor var. transvaalensis (E.Phillips & Schweick.) Beentje. The genus belongs to the family Asteraceae, order Asterales.
