[Illustration]
1. Fruiting portion in the middle of the frond; two to four pairs of
fertile pinnæ.
Interrupted Fern. _Osmunda Claytoniana_.
[Illustration]
2. Fruiting portion at the apex of the frond. Sterile pinnæ palmate; rachis
twining.
Climbing Fern. _Lygodium_.
[Illustration]
Sterile pinnæ pinnate; fronds large, fertile portion green, turning brown,
forming a panicle at the top.
Royal Fern. _Osmunda regalis_.
[Illustration]
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_.
[Illustration]
Sterile portion more or less divided; fruit in racemes or panicles, rarely
in spikes.
Grape Ferns. Moonwort. _Botrychium_.