SORI are usually elongate, and borne on the lower surface of leaves. They are either covered with an indusium, or found within a pouch formed by the indusium and opposed marginal leaf tissue. The annulus is vertical, well-developed, and interrupted by the stalk.
Spores are consistently monolete, and usually ellipsoidal.
They are indurated, and may branch. Stems bear scales and, rarely, also trichomes. They lack stipules, and have two to several vascular bundles. Circinate in bud, they range from 1 cm to 3 m in length. It may be glabrous or bear trichomes.