Aponogeton abyssinicus is an amphibious plant found in East Africa, from Ethiopia to Malawi and Zaire. Root stock tuberous or oblong, up to 2.5 cm diameter. Submersed leaves initially strap-shaped, up to 12 cm long and 6 mm wide, continuing lanceolate to obovate, up to 8.5 cm long, 2.6 cm wide and up to 10 cm long petiolate. Blade thin and slightly transparent, with a narrowing or decurrent base and acute or obtuse apex. Adults floating, up to 50 cm long petiolate. Floating leaf blade linear to ovoid, rarely cordate, up to 16 cm long and 5 cm wide, usually considerably smaller. Emersed leaves shaped like the floating leaves, slightly leathery and shorter petiolate. Peduncle up to 45 cm long, angled, dark red to green coloration, slightly pubescent underwater, almost glabrous above water, not swollen under the inflorescence. Spathe 1.0-1.6 cm long, caducous. Inflorescence featuring two 1.5-5-cm long spikes with omni-lateral flowers; 2 tepals, violet or white coloration; 6 stamens (none in apomictic plants); 3 carpels (up to 7 in apomictic plants). Fruit up to 7 x 2.75 mm large, with (4-) 7-10 seeds, sized 1-2 x 0.75 mm, double testa.