Pteridaceae

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Pteridaceae
Pityrogramma austroamericana
Scientific classification
Kingdom: Plantae Division: Pteridophyta Class: Pteridopsida Order: Pteridales Family: Pteridaceae
Genera
See text.

Pteridaceae is a large family of ferns in the order Pteridales. Members of the family have creeping or erect rhizomes and are mostly terrestrial or epipetric (growing on rock). The leaves are almost always compound and have linear sori that are typically on the margins of the leaves and lack a true indusium, typically being protected by a false indusium formed from the reflexed margin of the leaf. The family includes four groups of genera that are sometimes recognized as separate families: the adiantoid, cheilanthoid, pteroid, and hemionitidoid ferns. Relationships among these groups remain unclear, and although some recent genetic analyses of the Pteridales suggest that neither the family Pteridaceae nor the major groups within it are all monophyletic, as yet these analyses are insufficiently comprehensive and robust to provide good support for a revision of the order at the family level. As traditionally defined, the groups within Pteridaceae are as follows:

• Adiantoid ferns; epipetric, terrestrial or epiphytic in moist habitats, rachis often dichotomously branching; sori relatively small and discrete with sproangia born on the false indusium rather than the leaf blade proper; only one genus:
  • Adiantum, the maidenhair ferns
• Cheilanthoid ferns; primarily epipetric in semiarid habitats; leaves mostly with well-developed scales or trichomes, often bipinnate or otherwise highly compound; sporangia mostly born in marginal sori with false indusia that are +/- continuous around the leaf margins; several genera, including:
  • Argyrochosma
  • Astrolepis
  • Cheilanthes, the lip ferns
  • Notholaena, the cloak ferns
  • Pellaea, the cliff brakes
• Pteroid ferns; terrestrial and epipetric in moist habitats; leaves mostly without prominent scales or trichomes, most often pinnate but sometimes more compound; sporangia born in marginal sori with false indusia that are +/- continuous around the leaf margins; several genera, including:
  • Pteris, the brakes
  • Onychium
  • Acrostichum
• Hemionitidoid ferns; terrestrial, epipetric or epiphytic in moist or semiarid habitats; leaves simple, pinnate, or more compound; sporangia born in linear non-marginal, exindusiate sori or sometimes in marginal sori; several genera, including:
  • Anogramma
  • Cryptogramma
  • Eriosorus
  • Hemionitis
  • Jamesonia
  • Pityrogramma