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Key to Pteris

Pteridaceae

Pteris

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(c) Keim, Mary - CC-BY-NC-SA, permission granted to NCBG
(c) Horn, Jay
1 Leaf blades 10-20 dm long and wide; leaf veins anastamosing except near the margins of the ultimate segments; [subgenus Campteria; section Tripedipteris]
1 Leaf blades < 6 dm long or wide; leaf veins entirely free.
  2 Pinnae strictly simple, without lobes or pinnules; outline of leaf blade lanceolate, typically > 3× as long as wide; [subgenus Pteris; section Pteris]
    3 Petioles sparsely scaly, especially upwards; petiole scales dark brown to black; pinnae articulate to the rachis, mostly at right angles to it; fertile pinnae (at least) strongly revolute, with little or none of the lower surface exposed
    3 Petioles densely scaly, the scales usually continuing upwards onto the rachis; pinnae not articulate to the rachis, mostly ascending (at an acute angle to the rachis); fertile pinnae with a planar margin, most of the lower surface exposed
  2 Pinnae (at least the basal ones) with at least 1-several lobes or pinnules (many lobes or pinnules in P. plumula); outline of leaf blade ovate to orbicular, typically nearly as wide as long (or to 4× as long as wide in P. plumula); [subgenus Campteria; section Creticae].
      4 Pinnae of mature leaves decurrent in the upper half of the leaf onto the rachis; [subgenus Campteria; section Creticae]
      4 Pinnae of mature leaves not decurrent or only the terminal pinnae decurrent.
        5 Mature leaves regularly 1-pinnate-pinnatifid to 2-pinnate; [subgenus Campteria; section Campteria]
        5 Mature leaves pedately lobed; [subgenus Campteria; section Creticae].
          6 Pinnae with broad white central stripe