6 POLYPODIACEAE 



2. Anemia adiantifolia (L.) Sw. Leaf-blades triangular-ovate, 12-20 cm. 

 long, on usually elongated petioles, slightly pubescent, pinnately decompound; ulti- 

 mate segments obovate or cuneate, striate above with numerous flabellate veins. 

 In sandy soil or coral rock, peninsular Florida. Also in tropical America. 



Family 4. CERATOPTERIDACEAE Underw. Floatikg Fern Family. 



Aquatic succulent plants, floating, or rooting in mud. Leaves of two kinds, 

 the sterile leaves floating or emergent, the sporophyls erect, the ultimate seg- 

 ments linear, the margin revolute and often meeting near the midrib. Sporanges 

 scattered in 1 or 2 longitudinal lines, nearly sessile, globose, thin-walled, with 

 a complete or vestigial ring. 



1. CERATOPTERIS Brongn. 



Characters of the family. Floating Fern. 



Mature sterile leaves floating; blades pentagonal, 20 cm. long or less, 2-4-pinnatifid. 



1. C. pteridoides. 

 Mature sterile leaves emergent; blades broadly deltoid, 25-50 cm. long, 2-pinnate. 2. C. delioidea. 



1. Ceratopteris pteridoides (Hook.) Hieron. Plants floating or partly sub- 

 merged and rooted. Larger floating leaves up to 25 cm. long, the petioles expanded, 

 bulbous, the blades pentagonal, 6-20 cm. long and broad, 1-3 times pinnatifid, the 

 ultimate segments broadly ovate or deltoid, or in succeeding leaves 2-4 times divided, 

 with narrowly oblong segments; leaves of rooted plants similar, but the stipe not 

 expanded; sporophyls up to 40 cm. long, the segments linear; annulus 4-10-celled. 



Florida. Also in Cuba, Guiana and Brazil. 



2. Ceratopteris deltoidea Benedict. Plants partly submerged. Mature sterile 

 leaves 25-50 cm. long, the petioles not bulbous, 10-20 cm. long; blades deltoid, 20-35 

 cm. long, 15-25 cm. broad, acute, 2-pinnate or pinnatifid, with 5-8 pairs of pinnae, 

 the lowest broadly deltoid, 3-4 cm. long, acute; sporophyls 40-65 cm. long, the stipes 

 flattened, the blades deltoid, up to 40 cm. long, 4 times pinnately divided, the ulti- 

 mate segments linear; annulus 40-50-celled. 



Florida and Louisiana. Also in Porto Rico and Jamaica. 



Family 5. POLYPODIACEAE R. Br. Fern Family. 



Plants various in habit. Rootstoeks creeping or horizontal, elongated, or 

 short and erect. Leaves various, coiled in vernation : blades simple, once or 

 several times pinnatifid or pinnate, or decompound. Sporanges borne either 

 promiscuously or in clusters (sori) on the lower side or margins of the leaf- 

 blades, stalked, provided with an incomplete vertical ring of thickened cells 

 (annulus) and opening transversely. Sori either with or without a membranous 

 covering (indusium). Prothallia green. 



A. Fertile leaf-blades flat, or the edges of the leaflets merely revolute. 

 Sori (or sporangiferous areas) without indusia. 



Sporanges covering the leaf-blades or portions of them in mass, evenly. 



Coarse swamp plants with erect tufted leaves: rootstoeks short. 1. Acrostichum. 

 Smaller mainly epiphytic plants with spaced spreading leaves 



upon scandent or creeping rootstoeks. 21. Stenqchlaena. 



Sporanges grouped in definite sori, these apart or at least not wholly 

 covering the leaf-tissue. 

 Sori mostly roundish to elliptical, not marginal. 

 Petioles not jointed to the rootstock. 



Sori elliptical, often curved: veinlets mostly joined in 



pairs, forming numerous parallel areoles. 27. Meniscium. 



Sori roundish or punctiform: veinlets free, or 1 or 2 



pairs joined. 26. Dryopteris. 



Petioles jointed to the rootstock. 



Veins free. 2. Polvpodium. 



Veins copiously anastomosing. 



Leaf-blades (in our species) pinnatifid. 3. Phlebodium. 



Leaf-blades (in our species) simple. 



Leaves relatively large; areoles in regular rows 



extending toward the margin. 4. Campyloneurum. 



Leaves smaller; areoles mostly irregular. 5. Phymatodes. 



Sori linear, or at least more or less confluent in a marginal or 

 submarginal line. 

 Leaf-blades 1-4-pinnate. 14. Notholaena. 



Leaf-blades simple. 



