Adiantum - Adiantaceae

Adiantum formosum R. Br.






Common name

Black stem maidenhair or Giant maidenhair


Rhizome widely creeping, scaly, branched and forming colonies; rhizome scales lanceolate in outline, 2–3 × 0.5 mm, pale brown. Fronds monomorphic, erect, tall and robust, up to 1.5 m tall. Stipe mostly 30–45 cm tall, purple-brown or black, shiny, rough and scaly at the base, glabrous above. Lamina (3–)4-pinnate; pinnules obcuneate to oblong or asymmetrically rhombic in outline, the upper and outer margin usually only slightly incised and mostly finely sharply toothed, the lower margin ± straight and entire, 7–15 × 3–7 mm, glabrous or hairy; rhachis dark brown to black, hairy, pinnule-stalklets 0.5–1.5 mm long. Sori 4–8 per pinnule, 2 per lobe, kidney-shaped, broadly lunate or oblong, 0.5–1.5 mm wide.


Naturalised in Tanzania.


formosum: from the Latin formosus meaning 'beautiful'.


Grounds derived from former rain forest at about 850-950 m.

Distribution worldwide

Africa, Australia, New Zealand.

Distribution in Africa

Tanzania .

Growth form



  • Verdcourt, B. (2002) Adiantaceae.Flora of Tropical East Africa, Pages 60 - 61.