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Key to Ferns (Filices).
- Stem not forked.
(a) Simple leaf-like, feather-like parted, or twice parted................................................................................................................................................................................................................................................................................................................................................................................................Plate I. (b) Feather-like divided................................................................................................................................................................................................................................................................................................................................................................................................Plate II. (c) Feather-like divided and parted: - narrow................................................................................................................................................................................................................................................................................................................................................................................................
Plate II. - less than 2 ft. long................................................................................................................................................................................................................................................................................................................................................................................................
Plate III. - 2 ft. or more long................................................................................................................................................................................................................................................................................................................................................................................................
Plates IV., V. (d) Twice feather-like divided................................................................................................................................................................................................................................................................................................................................................................................................Plates VI. (e) Twice divided and parted, at least the lower leaflets................................................................................................................................................................................................................................................................................................................................................................................................Plates VI., VII., VIII. (f) Three times divided, at least the lower leaflets................................................................................................................................................................................................................................................................................................................................................................................................Plate IX. - Stem two-forked. Ferns................................................................................................................................................................................................................................................................................................................................................................................................
Plate X. - Evergreens or Club-mosses................................................................................................................................................................................................................................................................................................................................................................................................
Plate XI.