588 FILICES. (FERNS.) 



1. ACROSTICHUM, L. 



Sporangia entirely covering the lower surface of the upper pinnaj. Veins 

 finely reticulated with oblong hexagonal meshes. — Tall Ferns, with pinnate 

 fronds. 



1. A. aureum, L. Fronds coriaceous ; pinnae short-stalked, lanceolate- 

 oblong, entire. — Coast of South Florida. — Fronds 4° - 8° high, dark green, 

 shining. 



2. POLYPODIUM, L. Polypody. 



Fruit-dots round, naked, mostly at the ends of the free or reticulated veins. — 

 Kootstocks creeping. Sterile and fertile fronds alike. 



§ 1. POLYPODIUM Proper. - Veins free. 



1. P. VUlgare, L. Fronds evergreen, smooth on both sides, oblong, 

 simply and deeply pinnatifid ; the divisions linear-oblong, obtuse, slightly 

 toothed ; fruit-dots large. — Mossy rocks, &c, in shady woods, in the upper 

 districts of Alabama, and northward. — Fronds 4'- 10' high. 



2. P. Plumula, Wtlld. Fronds linear-lanceolate, narrowed at both ends, 

 pinnatifid to the black and somewhat chaffy midrib ; the divisions very numer- 

 ous, narrowly linear, entire, wider at the base ; fruit-dots small. — Tampa Bay, 

 Dr. Leavenworth. — Fronds 12' -18' high, 18" -24" wide. 



3. P. hexagonopterum, Michx. Fronds annual, broadly triangular, 

 bipinnatifid ; pinnae lanceolate, acuminate, spreading, the lower pair erect; pin- 

 nules oblong, mostly obtuse, crenately toothed or entire ; fruit-dots numerous, 

 minute. — Shady woods, Florida to Mississippi, westward and northward — 

 A foot or more high from an elongated creeping rootstoek. Pinnae decurrent, 

 forming irregular hexagonal wings on the rachis. 



§ 2. MARGIN ARIA, Bory. — Veins obscure, sometimes reticulating near the 

 margin. Stipe and lower surface of the frond covered with chaffy scales. 



4. P. incanum, Swartz. Fronds evergreen, coriaceous, beneath thickly 

 beset with peltate chaffy scales, smooth and green above, pinnately parted; the 

 divisions oblong, obtuse, entire ; fruit-dots near the margin. — On trunks of trees, 

 Florida to Mississippi, westward and northward. — Rootstoek chaffy, creeping. 

 Fronds 3' - 8' high. 



$ 3. CAMPYLONEURUM, Presl. — Veins parallel, pinnate from the midrib: 

 veinlets reticulated, forming a series of parallel angular arcs with short ve inlets pro- 

 ceeding from their aughs. Fronds simple. 



5. P. Phyllitidis, L. Fronds linear-lanceolate, entire, acuminate, of a 

 thin chartaccous texture, scmi-pcllucid ; fruit-dots rather large, in two rows 

 bet ween the veins. — South Florida. — Fronds 1° -2° high. 



$ 4. PHLEBODIUM, R. Br. — Veins pinnate from the midrib, furcate: veinlets 

 reticulated in mostly elongated meshes. Fruit-dots large, commonly at the extremities 

 of two converging i\ inlets. 



6. P. aureum, L. Fronds smooth and glaucous, broadly ovate, pinnately 



