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....3 Sterile blade palmately lobed with 2-11 lobes, the blade usually wider than long or nearly so; fertile portion of blade (1-) 2-15 per leaf
....3 Sterile blade strap-shaped, entire or rarely once or twice dichotomously lobed, the blade much longer than wide; fertile portion of blade 1 per leaf
..2 Plants terrestrial; sterile leaf blades unlobed, to 5 cm wide; main areoles of anastamosing veins mostly < 6 mm long; [collectively widespread]
......4 Fertile stalk joined to the stalk of the sterile leaf blade near the rhizome, far below the base of the leaf blade, and usually at or below the surface of the ground; leaves evergreen, appearing in spring, summer, or fall, and withering the following spring; sterile leaf blades triangular (or pentagonal) in general outline
......4 Fertile stalk joined to the stalk of the sterile leaf blade near the base of the leaf blade, far above the rhizome, and usually well above the surface of the ground; leaves deciduous, appearing in spring and withering the same summer or fall; sterile leaf blades either triangular (or pentagonal) or elongate in general outline.
........5 Sterile leaf blade 1-pinnatifid or 1-2-pinnate; plants usually < 20 cm tall; sterile blade fleshy in texture, 1-8 cm long
........5 Sterile leaf blade 3-ternate or even more finely divided; plants (9-) 30-50 cm tall; sterile blade herbaceous in texture, 10-40 cm long