_POLYPODIÀCEÆ_
Green, leafy plants whose spores are borne in spore-cases (sporangia),
which are collected in dots or clusters (fruit-dots or sori) on the back
of the frond or form lines along the edge of its divisions. Sporangia
surrounded by vertical, elastic rings bursting transversely and scattering
the spores. Fruit-dots (sori) often covered, at least when young, by a
membrane called the indusium. Spores brown.