Sporangia borne along the inrolled margins of frond segments or in linear sori beneath indusia that extend inward from the margins (ferns lacking sporangia on even the largest fronds, having ternate fronds with inrolled margins, should be keyed out here).

Sporangia borne in distinct (although sometimes crowded) sori, the sori either not marginal, or if marginal then roundish or reniform.