2024 Edition • Donate • Get the App • Cite this Page
X

Colors

Data mode

Account

Login
Sign up

Support FSUS...

We've finished our 2024 fundraiser. Many thanks to those who have given! It's not too late to support us (click here)...

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Adiantum

Copy permalink to share

1 Petioles and rachises pubescent; [of the Coastal Plain of FL, GA, AL, and LA].
  2 Leaves broader than long, dichotomously divided at the summit of the petiole, the two main branches pedately branched, fanlike; ultimate leaf segments hairy with multicellular hairs on the lower surface; rachises hispid; false indusia roundish; [formosum clade]
  2 Leaves longer than broad, pinnately divided, with a main central axis, not fanlike; Ultimate leaf segments glabrous on the lower surface; rachises strigose; false indusia crescent-shaped.
    3 Leaf segments glaucous below; [peruvianum clade]
    3 Leaf segments green below; [tetraphyllum clade]
1 Petioles and rachises glabrous; [collectively widespread].
      4 Leaves broader than long, dichotomously divided at the summit of the petiole, the two main branches pedately branched, fanlike; ultimate segments oblong, > 2× as long as broad; [pedatum clade]
      4 Leaves longer than broad, pinnately divided, with a main central axis, not fanlike; ultimate segments rhombic, about as long as broad (usually 0.7-1.3× as long as broad).
        5 Leaflets 2-8 cm long, 1-7 cm wide; [of s. FL]; [peruvianum clade].
          6 Leaflets 5-8 cm long, 2.5-7 cm wide
          6 Leaflets 2-5 cm long, 1-3 cm wide
        5 Leaflets 0.5-3 cm long, 0.5-3 cm wide; [collectively more widespread].
             7 Blackish-brown color of the stalks extending into the base of the ultimate segments, making 1 or 2 dichotomous branchings before fading to green; [of VA, KT, and MO southwards]; [capillus-veneris clade]
             7 Blackish-brown color of the stalks ending abruptly at the base of the ultimate segments in a cupule-like swelling (use at least 10× magnification); [of n. FL southwards]; [tenerum clade]