Brachystephanus africanus photographed on Mabu Mountain.
Brachystephanus africanus S.Moore
Least Concern (LC) according to IUCN Red List criteria.
Understorey in tropical forests.
About this species
Brachystephanus africanus has long been known to occur in central and eastern Africa, and in Madagascar, but in 2008 Stephen Mphamba collected the first specimen of this species in Mozambique during Kew-led fieldwork on Namuli Mountain. Since then it has also been collected on the nearby Mabu Mountain (also in Mozambique).
There are currently three recognised varieties: B. africanus var. africanus (only found in tropical forest on mountains and the variety that occurs in Mozambique), B. africanus var. recurvatus (found on mountains in the Democratic Republic of Congo), and B. africanus var. madagascariensis (found in Madagascar).
The Madagascan sub-group is clearly geographically separated from the other sub-groups, while the ranges of the East African and Congolese subgroups overlap geographically. As the structural differences seen in the plants are not significantly greater between the subgroups that geographically overlap compared to those that are separated, the decision was made to classify the three different subgroups as varieties.
Geography and distribution
Native to the Democratic Republic of Congo, Uganda, Tanzania, Malawi, Mozambique and Madagascar.
Brachystephanus africanus is a herb that produces fresh stems from a woody base. It grows to 0.3–2 m tall and has leaves 5.5–24 cm long and 1.8–10 cm wide, with a petiole (leaf stalk) 0.7–6.2 cm long.
The inflorescence takes the form of a spike of flowers and is 5.5–25 cm long. It bears bracts (small, leaf-like, flower-protecting structures) 5–25 mm long, 1.7–6.5 mm wide, which are dark green or tinged pink, purple or red-brown with somewhat transparent margins and a group of hairs usually restricted to the tip. The inflorescence also bears bracteoles (even smaller, leaf-like, flower-protecting structures) 2–6.5 mm long and 0.5–1 mm wide, also with transparent margins. The calyx lobes (outer protective structures of the flower) are 2.5-17 mm long. The flowers are mauve, violet, blue, rose or red, and are 29-51 mm long. The tube of the flower is narrowly cylindrical, 22–38 mm long and covered with short hairs. The upper lip of the flower is 6.5–13.5 mm long and 5.5–8 mm wide, with the tip ending in a small, projecting point. The lower lip of the flower is 7–14.5 mm long and 6–8.5 mm wide. The stamens (male parts) are 13.5–36 mm long and project out of the flower. The style (female part) is 35–75 mm long.
The fruit is a hard capsule, 11.5–15 mm long.
In Brachystephanus africanus var. africanus the tip of the bract is either straight or bent inwards, distinguishing it from B. africanus var. recurvatus, which has bracts with outward-bending tips. (In B. africanus var. madagascariensis the bracts are unlike those of the other varieties as they are widest near their tip and the tip is slightly outwardly bent but not completely revurved).
Threats and conservation
Brachystephanus africanus has been assessed as Least Concern as it is widespread and often locally abundant.
Millennium Seed Bank: Seed storage
The Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in Kew's seed bank vault at Wakehurst.
Collections stored in the Millennium Seed Bank: One
This species at Kew
Several dried and pressed specimens of Brachystephanus africanus are held in Kew’s Herbarium, including a type specimen. The details of some of these specimens can be seen online in the Herbarium Catalogue. Herbarium specimens are also available to researchers by appointment.
Darbyshire, I., Vollesen, K. & Kelbessa, E. (2010). Flora of Tropical East Africa: Acanthaceae. Royal Botanic Gardens, Kew.
Kew Science Editor: Tim Harris
Kew contributors: Iain Darbyshire
Copyediting: Emma Tredwell
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