Fissidens dubius P. Beauv., Prodr. Aethéogam. 57. 1805. Type. United States of America,
s. coll. (GL).
Fissidens cristatus Wils. ex Mitt., J. Linn. Soc., Bot. Suppl. 1: 137. 1859. Type. India, Hooker & Thompson s.n. (BM).
Plants to 2.5 cm × ca. 3.5 mm. Leaves to 3.5 mm × ca. 0.7 mm; apex obtuse to acute, often apiculate; margins crenulate-serrate at apices, elimbate; vaginant laminae more or less 2/3 the leaf length, unequal, minor laminae acute; costa percurrent to ending a few cells below apex; cells 7–10 µm, irregularly bistratose, smooth but bulging, rounded-hexagonal. Sporophytes lateral.