[*] Sporangia at the ends of the veins, on a reflexed portion of the margin of the frond.
3. Adiantum. Midrib of the pinnules marginal or none. Stipe black and polished.
[*][*] Sporangia borne on a continuous marginal vein-like receptacle, connecting the apices of the veins, and covered by a delicate whitish indusium formed of the reflexed margin.
4. Pteris. Midrib of the pinnules central. Stipe light colored.
[*][*][*] Sporangia at or near the ends of the unconnected veins, borne on the under surface of the frond; indusium various.
5. Cheilanthes. Sori minute, at the ends of the veins; indusium continuous or interrupted. Fronds mostly chaffy, woolly, or pulverulent, rarely smooth.
6. Pellæa. Sori on the upper part of the veins, distinct, or mostly forming a confluent submarginal band of sporangia. Indusium membranaceous, continuous, rarely wanting. Sterile and fertile fronds not very unlike; stipes dark colored; fronds smooth.
7. Cryptogramme. Sori roundish or elongated and extending far down the free veins, at first covered by the very broad continuous indusium, at length exposed and confluent. Sterile and fertile fronds very different; stipes light colored; fronds smooth.
Tribe IV. BLECHNEÆ. Sori oblong or linear, borne on a veinlet parallel to the midrib, and covered with a special usually concave or arched indusium attached to the fruiting veinlet, and opening along the inner side.
8. Woodwardia. Sori forming a chain-like row each side of the midrib or central vein. Veins reticulated.