Floating form: stipe up to 30 cm long. Leaflets up to 25 × 17 mm, broadly obovate to broadly obdeltate, outer margin rounded, entire to shallowly sinuate, hairless, with brown interstitial streks below. Dry land form: stipe up to 4.5 cm long. Leaflets up to 10 × 7 mm, narrowly cuneate to broadly obdeltate, outer margins rounded to truncate, finaly set with long hairs. Sporocarps: usually in clusters of 2 or more, roughly square in lateral view, upper side straight, under side rounded, outer side rounded, lateral surfaces with a broad, somewhat curved, vertical furrow, oblong and grooved from the front; densely hairy when young becoming subglabrous with age; inferior tooth absent, superior tooth prominent, acute; pedicels up to 8 mm long, long, erect, twisted or straight, free, 2 or more arising from the axil of the stipe.

The sporocarps of M. aegyptiaca have a backward-facing lateral groove, this is not found in other Marsilea species from southern Africa.

aegyptiaca: from Egypt, the species was first collected in Egypt.

Arid semi-desert, growing along the margins of seasonal pans, pools and briefly flowing rivers.

Africa, Madagascar and probably India.

Algeria, Botswana, Egypt, Ethiopia, Libya, Mali, Morocco and Western Sahara, Namibia, Sudan and South Sudan, Tunesia.

Aquatic, terrestrial.