Flora of the Southeastern United States

1 Leaves unlobed.

  2 Sori elliptical or oblong, in 1 row on either side of the midvein, the row ½ to 2/3 of the way between the midvein and the margin

1 Leaves pinnatifid.

    3 Laminar scales of the upper leaf surface absent or essentially so; glands inconspicuous, on the proximal acroscopic side of the basal pinnae; rhizome scale margins strongly erose-serrate; laminar scales of the lower leaf surface sparse, lanceolate, sometimes touching, their margins undulate, entire; orbicular scales present and readily visible; [widespread in our area]

    3 Laminar scales of the upper leaf surface bearing scattered scales, these subulate, the base pectinate-stellate, apex long caudate, margin weakly erose; glands conspicuous, round to elliptic, rather swollen with a central depression, on a small auricle within the sinus near the acroscopic side of the basal pinnae; rhizome scale margins erose-ciliate; laminar scales of the lower leaf surface dense, lanceolate, their margins ciliate (peripheral scales often extending beyond the margin of the blade); orbicular scales present, but not readily visible; [FL Keys only]

1 Leaves entire, unlobed.

  2 Sori discrete, round, elliptical or oblong.

    3 Leaf blade scaly on the lower surface with peltate, bicolored scales; stems (rhizomes) long-creeping, ca. 1 mm in diameter, the leaves scattered; [subfamily Polypodioideae]

    3 Leaf blade scaleless on the lower surface; [subfamily Campyloneuroideae]

      4 Stems (rhizomes) short-creeping, 2-10 mm in diameter, the leaves clustered; main lateral veins either readily apparent (and then parallel to one another or obscure

      4 Stems (rhizomes) long-creeping, 0.5-1.5 mm in diameter (3-6 mm in M. nitida), the leaves spaced along the rhizome; main lateral veins obscure, anastamosing

1 Leaves either pinnatifid to 1-pinnate, or palmately and dichotomously lobed.

        5 Leaves palmately lobed, the lobes branching dichotomously; foliage indument of stellate hairs; [subfamily Platycerioideae]

        5 Leaves pinnatifid or pinnate (the lobes arrayed along an axis); foliage indument absent or of simple hairs or scales.

          6 Leaves 1-pinnate; [subfamily Serpocauloideae]

          6 Leaves simple, 1-pinnatifid.

             7 Plants dwarf, the leaf blades < 5 cm long; [occurring only in habitats where the air is constantly humid and the substrate saturated, as in grottoes behind waterfalls]; [subfamily Grammitidoideae]

             7 Plants larger, the leaf blades 7-90 cm long; [occurring in moist to dry habitats].

               8 Leaf blade densely scaly on the lower surface with peltate, bicolored scales; rhizome 1-2 mm in diameter; leaf segment margins entire; [subfamily Polypodioideae]

               8 Leaf blade scaleless on the lower surface; rhizome 3-15 (-30) mm in diameter; leaf segment margins denticulate (Polypodium) or entire (Pecluma, Phlebodium, Phymatosorus).

                 9 Larger leaves with > 25 pairs of segments, each 1.5-5 (-8) mm wide; [of ne. FL southward]; [subfamily Polypodioideae]

                 9 Larger leaves with < 25 pairs of segments, each (3-) 5-40 mm wide; [collectively widespread in our area.

                   10 Venation free or with a row of areoles between the pinnae midveins and margins; rhizome 3-6 mm in diameter; leaf blade < 9 cm wide; [subfamily Polypodioideae]

                   10 Venation highly reticulate, with 3-4 rows of areoles between the pinnae midveins and margins; rhizome 3-30 mm in diameter; leaf blade 10-50 cm wide.

                     11 Sori borne in distinct depressions in the blade surface; rhizome 3-6 mm in diameter; sori in (1-) 2-3 rows on each side of the costa; [subfamily Microsoroideae]

                     11 Sori borne on the planar blade surface or slightly sunken; rhizome 8-30 mm in diameter; sori in 1-2 row on each side of the costa; [subfamily Polypodioideae]

                       12 Plant with 2 distinct frond types, sessile nest fronds with shallow lobes ("oaklike") which turn a light coppery brown, and long-petiolate foliage fronds which are green and pinnatifid with deep sinuses; [subfamily Crypsinoideae]

                       12 Plant lacking nest fronds, only bearing long-petiolate foliage fronds with deep sinuses; [subfamily Polypodioideae]