Marsilea fenestrata Launert

Plants seasonally aquatic. Rhizome wide-creeping, initially green, brown later, firm, herbaceous, terete, to 1 mm in diameter, branched, rooting at the nodes, internodes to 35 mm long, initially sparsely pilose, glabrous later, hairs ventrally attached, filiform, to 1 mm long. Stipe slender to stout, green initially, brown later, terete, to 120 mm long, initially moderately appressed pilose, glabrous later, hairs hyaline to pale brown, laterally attached, filiform, to 1.5 mm long; pinnae herbaceous, pulvinate, obdeltate to broadly obdeltate, flanks straight or slightly convex, outer margin convex, entire, with long pellucid streaks between the veins, glabrous adaxially, abaxially with scattered hairs, hairs hyaline, ventrally attached, fusiform, to 0.3 mm long. Venation obscure, free or anastomosing, terminal vein branches anastomose to form a near-marginal commissure. Sporocarps in dense groups of 7 to 8, at the very base of the stipes, pedicels simple, to 3 mm long, subrectangular in lateral view, narrowly-elliptic in dorsiventral cross-section, dorsally slightly inwardly curved, ventrally curved, to 3.5 mm long, to 2.6 mm high, strigose initially, glabrous later, 4-7 lateral ribs almost invisible in mature sporocarps, not anastomosing, raphe distinct, attached along the entire base of the sporocarp, inferior tooth obtuse, not very prominent, superior tooth conspicuous, slender, tapering from a cone-shaped base, acute, straight or slightly curved.