Floating form: stipe up to 20 cm long; leaflets obdeltate, 4-16 × 2-15 mm, outer margin rounded, shallowly sinuate to scalloped, hairless, with translucent streaks between the veins. Dry land form: stipe 2.5-9 cm long, leaflets narrowly obdeltate, 4-12 × 2-8 mm, outer margins deeply sinuate to incised, thinly set with long hairs above, sparser below, translucent streaks present. Sporocarps: clustered in fairly dense groups, ± 3.5 × 3 mm, roughly rectangular in outline, upper side straight to slightly concave, lower side curved, narrowly elliptic in dorsoventral cross-section; hairy when young becoming subglabrous when mature; lower tooth a shallow hump, upper tooth prominent, sharply acute, frequently curved; pedicels 2.5-7 mm, somewhat curved, ascending, free, many arising from the axils of the stipes.

Differs from M. ephippiocarpa by having sporacarps with unbranched, free, not united pedicels, leaves have distinctive translucent streaks.

fenestra: with windows; referring to the translucent, longitudinal streaks in the leaflets.

In mud on the edge of seasonal pans.

See African distribution.

Mozambique, South Africa, Swaziland.

Aquatic, terrestrial.