Asplenium - Aspleniaceae

Asplenium unilaterale Lam.

Photo: P. Ballings

Photo: P. Ballings






Asplenium resectum Sm.
Hymenasplenium unilaterale (Lam.) Hayata
Asplenium unilaterale Lam. var. majus (C.Chr.) Sledge

Common name


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.


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.


unilaterale: one-sided, referring to the form of the pinnae.


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.


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  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Page 222. (Includes a picture).
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