The stems have a broad, starch-rich cortex, and may be subterranean or aerial in different species.
Leaves are pubescent when young.
Male sporophylls carry numerous sporangia on the under- or abaxial surface, and sporangia open by slits to shed pollen. Pollen is weakly ornamented, cymbiform, monosulcate, and bilaterally symmetrical. Male gametophytes are large, multiflagellate and motile. Endosperm is haploid, derived from the female gametophyte. The embryo is straight, with 2 cotyledons which are usually united at the tips, and germination is cryptocotular.