Species

Asplenium unilaterale Lam.

Photo: P. Ballings
Zimbabwe

Synonyms	Asplenium resectum Sm. Hymenasplenium unilaterale (Lam.) Hayata Asplenium unilaterale Lam. var. majus (C.Chr.) Sledge
Common name
Description	Rhizome creeping, c.3 mm thick; rhizome scales 2-3 mm long, dark brown, lanceolate, margins entire. Fronds spaced apart, erect, herbaceous. Stipe 7.5-22 cm long, stipe and rhachis glabrous, dark brown to almost black. Lamina 17-30 × 5-10 cm, pinnate, narrowly elliptic to oblong in outline, lowest pinnae hardly reduced but often more lobed, apex decrescent and tapering to a point. Pinnae 12-20 pairs, glabrous, narrowly triangular-rhombic or shaped like a parallelogram, up to 3.5-6 x 0.5-1.2 cm, upper margin toothed to lobed, costa forming the lower margin for about 1/2 to 3/4 of the pinna length. Sori 2-10(-14), oval-linear, set along the veins towards the apex of the pinnae, 2.5-3 mm long; indusium narrowly oblong, membranous, entire, 0.8 mm wide.
Notes	This taxa is easily recognisable by the costa forming the lower edge of the pinna for 1/2 to 3/4 of its length. and differs from A. obscurum by having a dark brown to almost black stipe and smaller sori (± 3 mm long) that are sparsely scattered towards the pinna apex.
Derivation	unilaterale: one-sided, referring to the form of the pinnae.
Habitat	Moist evergreen or riverine forest, deeply shaded stream banks or near waterfalls.
Distribution worldwide	Africa, Mascarene Isl., Pacific Isl., S and E Asia.
Distribution in Africa	Angola , Cameroon , Central African Republic , Congo , Equatorial Guinea (incl. Bioko), Ethiopia , Ghana , Guinea , Ivory Coast , Kenya , Liberia , Malawi , Niger , Nigeria , Sierra Leone , Sudan and South Sudan , Swaziland , Tanzania , Uganda , Zimbabwe .
Growth form	Lithophytic, terrestrial.
Literature	Beentje, H.J. (2008) Aspleniaceae.Flora of Tropical East Africa, Pages 28 - 29. (Includes a picture). Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Page 222. (Includes a picture). Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature. Pages 600 - 601. (Includes a picture). Fisher E. & Killmann D. (2008) Illustrated Field guide to the Plants of Nyungwe National Park Rwanda. University of Koblenz-Landau. Pages 68 - 69. (Includes a picture). Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 340 - 341. (Includes a picture). Roux, J.P. (2009) Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23, South African National Biodiversity Institute, Pretoria. Pages 99 - 100. Roux, J.P. (2001) Conspectus of Southern African Pteridophyta.Southern African Botanical Diversity Network Report, 13 Page 172. (Includes a picture). Schelpe, E.A.C.L.E. (1970) Pteridophyta.Flora Zambesiaca, 0 Page 174. Tardieu-Blot, M.-L. (1964) Ptéridophytes vol.3.Flore du Cameroun, Pages 195 - 196. (Includes a picture).