Calamaria schweinfurthii A. Braun ex Baker
Isoetes rhodesiana Alston
Isoetes kersii Wanntorp

Pseudo-corms 3-lobed; bud scales dark brown to blackish, triangular-cuspidate, ± 6 × 4 mm. Leaves 5-40, narrow, stiff, 150-600 × c.1 mm (at apex) - c.10 mm (around sporangium), broadly winged, apex tapering to a point. Ligule narrowly triangular, sides convex, abruptly pointed, 2-6 mm long, pale, covered by a membranous serrate lip in the lower half. Velum absent or reduced to a vestigial rim. Sporangia 4-12 × 5-9 mm, oblong-obovate to circular. Megaspores 0.4-0.5 mm in diameter, ash-grey to whitish, upper surface almost smooth or with a few tubercles, lower tuberculate with conical warts. Microspores not seen.

I. alstonii is distinguished from I. schweinfurthii by its 2-lobed pseudo-corm. I. schweinfurhii is separated from I. aequinoctialis by lacking a velum.

schweinfurthii: named after Dr Georg August Schweinfurth (1836-1925), German botanical collector and taxonomist.

Shallow seasonally inundated pans in dry deciduous woodland or sometimes in sandy soils overlying sheetrock along river margins.

Africa, Madagascar.

Angola, Benin, Burkina Fasso, Burundi, Central African Republic, Chad, Ethiopia, Ivory Coast, Kenya, Malawi, Morocco and Western Sahara, Mozambique, Namibia, Senegal, South Africa, Sudan and South Sudan, Tanzania , Zambia, Zimbabwe.

Terrestrial.