_OPHIOGLOSSÀCEÆ_
Plants more or less fern-like consisting of a stem with a single leaf. In
_Ophioglóssum_ the leaf or sterile segment is entire, the veins reticulated
and the sporangia in a simple spike. In _Botrýchium_ the sterile segment is
more or less incised, the veins free, and the sori in a panicle or compound
or rarely simple spike. Sporangia naked, opening by a transverse slit.
Spores copious, sulphur-yellow.