Isoetes schweinfurthii A. Br.

alstonii: named after A.H.G. Alston (1902-1958), Britisch botanist specialised in African pteridophytes.

Pseudo-corm 10-20 cm in diameter, 2-lobed; bud scales vestigial or lacking. Leaves 10-40, linear, 130-400 mm × 1 mm (apically)- 6 mm (at base),apex tapering to a point, yellow to midgreen, semi-circular in cross-section, abruptly ovate-oblong at the base, with broadly hyaline wing, stomata present in upper parts of the leaves. Ligule 1-2 × c. 1.5 mm, hyaline, triangular, pointed. Velum very narrow, reduced to a thin marginal ring. Sporangia 4-10 × 3-6 mm. Megaspores of 2 sizes, 0.52 and 0.3 mm in diameter, dark grey, drying white, usually 3-radiate, with large warts below, granulated above.

Ethiopia, Mozambique, Namibia, Tanzania, Zambia, Zimbabwe.