20 FAM. 3. 



O. cinnamomea, Cinnamon Fern. Cluster of erect sterile leaves with few fertile 

 ones from the creeping rootstock; petioles tomentose when young; leaflets 

 pinnatifid; sporophyl 2-pinnate; sporanges cinnamon-colored; the fertile 

 leaves wither before the sterile ones expand. Some fronds are partly sterile 

 and partly fertile. Low wet places. 



3. Polypodiaceae, Fern Family. 



Leaves coiled in vernation; sporanges in sori on the 

 back or along the margin of the blades, and provided with 

 an annulus. 



1. Sori without indusia, - _______--2 



1. Sori with indusia, - -- _ _ _ _ 4 



2. Sori in masses covering the under surface of the leaf -blades partly or 



totally, _________ Acrostichum 



A. aureum. Tall swamp-plants with erect massed rootstocks and tufted leaves, 

 1-2 m. long; petioles erect, angular grooved; blades leathery, glossy, 3-4 

 dm. wide; leaflets about 12 pairs; areolae without free veinlets, oblique to 

 the margin; sori covering part of the leaves. Green Springs, near Enter- 

 prise, and South. 

 A. lomarioides. Leaflets about 24 pairs; areolae facing the margin; sori covering 

 the whole leaves. Ponds and wet ground. 

 2. Sori roundish, -______--_-_ 3 



2. Sori linear, more than twice as long as broad, - Vittaria 



V. lineata, Crass Fern. Leaves grass-like; sori in a continuous groove near 

 the margin of the blade; veins obscure. On palmetto. 



3. Veins free, - ______ -- Polypodium 



P. polypodioides (incanum), Resurrection Fern. Leaves coriaceous, pinnately 



parted, small; petioles and back of blades with peltate scales; veins ob- 

 scure. An evergreen on rocks and trunks of trees, especially oaks. 



P. pectinatum. Leaves about 1 m. long, deeply pinnatifid, without scales; veins 

 2-3 forked, pellucid. On trees. 



P. plumula. Leaves about 5 dm. long, petioles black, blades without scales; 

 veins 1-forked, obscure. Hammocks. 



3. Veins anastomosing, forming areolae which include free vein- 



lets, at the end of which the sori appear. - - Phlebodium 



P. (Polypodium) aureum. Petioles chestnut-colored, blades ample, cut nearly 

 to the rachis; segments entire, undulate. On palmetto and cultivated 

 in pots. 



4. Indusia formed by the margin of the leaf-blade, --___- 5 



4. Indusia specially developed, sori dorsal, __---__7 



5. Sporanges in intramarginal lines which connect the ends of the veins, - - 6 



5. Sporanges in reflexed portions of the leaf-blades at the ends 



of the veins, -_-___-- _ Adianthum 

 A. Capillus- Veneris, Venus-hair. Petioles slender and shining; leaves ovate- 

 lanceolate, 1-2 pinnate. On limestone and cultivated. 

 A. tenerum, Maidenhair. Petioles slender and shining; leaves deltoid; 3-4 



pinnate. In lime-sinks. 

 Several species of Adianthum are cultivated as A. cuneatum, A. hispidulum, 

 A. hybridum, A. farleyense, A. caudatum, A. lunulatum; the latter two 

 are "walking ferns." 



6. Indusium single, -_____--_- Pteris 



