Isoetes pusilla

Leaves erect or recurved, 2–6 cm long; base dilated, overlapping, spoon-shaped, lateral margins translucent. Megasporangia orbicular to elliptical, 2–3 mm long, wall pale, thin, usually covered completely by membranous velum; megaspores 10–20 per sporangium (in outer leaves), whitish-grey, monomorphic, spherical; surface ornamented with narrow, low, sharp, anastomosing ridges which become netted on distal faces. Microsporangia present, microspores numerous.