Rhizome pear-shaped to rounded or narrowly oval, (1.5-)3-11(-19) × 1-5 mm; roots dense, descending, wiry, proliferous. Leaves mostly 2 (1-3), held at 20° from the horizontal or appressed to the ground, dark green often with a reddish to orange coloration. Stipe up to 2 cm long, subterranean for most of its length (75-90%), stipe:lamina lenght ratio 1.7-1.2:1. Sterile lamina up to 17 × 10 mm, elliptic to broadly ovate in outline, apex pointed to sometimes rounded, base wedge-shaped to truncate, with an apparent pale pseudo-midrib formed towards the base of the lamina only. Fertile segment up to 7.2(-9.3) cm long, inserted at the base of the lamina, fertile spike:lamina lenght ratio 2.1-5.6:1. Sporangia 3-17 pairs, apex pointed.

Could be mistaken for O. costatum which usually has dull green leaves that are held at 60-80° of the ground and a prominent pale pseudo-midrib. O. convexum has linear dull green leaves held at 0-30% from the horizontal, the pale pseudo-midrib is absent.

rubellum: reddish; referring to the reddish to orange coloration present in the leaves.

Seasonally moist sandy soils overlying granite or sandstone in mixed deciduous woodland.

See African distribution.

Angola, Benin, Central African Republic, Ethiopia, Gabon, Ghana, Kenya, Malawi, Sierra Leone, South Africa, Tanzania , Uganda, Zambia, Zimbabwe.

Terrestrial.