Ophioglossaceae -- the grape-fern family (3-5/70-80; tropic and temperate)
Plants homosporous
Habit herbs with short erect, unbranched stems
Leaves solitary or alternate; sterile frond is simple to much dissected or compound and fertile frond resembles a spike or panicle; dimorphic, but both fronds borne as a pair, and are usually partially fused at the base into a solitary structure
Vernation not circinate
Sporangia eusporangia (large sporangia without an annulus) borne on fertile frond
Spores numerous, small, uniform in size
Gametophytes bisexual, fleshy, subterranean, mycotrophic