OPHIOGLOSSACEAE (Adder's Tongue
Family)
(Clausen, 1938)
Plants perennial, homosporous, with fleshy roots and short, erect stems, these
sometimes cormlike. Leaves divided along the petioles into fertile and
vegetative portions. Petioles with scalelike, sheathing, stipular flanges of
tissue. Vegetative leaf blades entire or variously compound. Fertile portions
of leaves branched or unbranched. Sporangia splitting open horizontally,
lacking an annulus. Spores trilete, 25–55 mm in diameter, light yellow to yellow, up to
15,000 per sporangium. Gametophytes subterranean, mycorrhizal, lacking
chlorophyll, cylindrical to nearly spherical. Three to 5 genera, 70–80 species,
nearly worldwide.