B. Fruiting Fronds Partly Sterile

1. Fruiting portion in the middle of the frond; two to four pairs of fertile pinnæ.

Interrupted Fern. Osmunda Claytoniana.

2. Fruiting portion at the apex of the frond. Sterile pinnæ palmate; rachis twining.

Climbing Fern. Lygodium.

Sterile pinnæ pinnate; fronds large, fertile portion green, turning brown, forming a panicle at the top.

Royal Fern. Osmunda regalis.

3. Fruiting portion seemingly on a separate stock a few inches above the sterile.

Sterile part an entire, ovate, green leaf near the middle; fertile part a spike.

Adder’s Tongue. Ophioglossum.

Sterile portion more or less divided; fruit in racemes or panicles, rarely in spikes.

Grape Ferns. Moonwort. Botrychium.