Submerged aquatic. Stock apparently 2-lobed, appressed-semiglobose c. 3.5 by 1½ cm across, 1 cm high, with numerous short, brownish-black roots 2 mm in diam. arising from the lower surface. Leaves numerous, up to 14 cm, stout, more or less recurved, c. 3 mm broad in the centre, semicircular in transverse section, rounded on the back and flattened above; central vascular strand rather prominent; margins slightly winged. Upper part of the leaves green, apices caducous. Lower part of leaves c. 3 cm long, pale reddish-brown, up to 1 cm broad and winged at base. Stomata none. Ligule deltoid. Velum none. Sporangia obovate-oblong, c. 1 cm by 4 mm, pale brown. Megaspores c. 575 μ, in diam., almost smooth, with a prominent triradiate marking, pale greyish-white when dry. Microspores c. 43 μ long, densely spinulose, brown when dry.
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