588 FILICES. (FEKNS.) 



1. ACROSTICHUM, L. 



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

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

 fronds. 



1. A. aureum, L. Fronds coriaceous ; pinnse 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 reins. — 

 Eootstocks creeping. Sterile and fertile fronds alike. 



<j 1. POLYPODIUM Peopee. — 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, Willd. 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 ; pinnse 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. Pinna; decurrent, 

 forming irregular hexagonal wings on the rachis. 



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

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



4. P. incauum, 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. — Eootstock chaffy, creeping. 

 Fronds 3' -8' high. 



§ 3. CAMPYLONEURUM, Presl. —Ferns parallel, pinnate from the midrib: 

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

 ceeding from their angles. Fronds simple. 



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

 thin chartaceous texture, semi-pellucid ; fruit-dots rather large, in two rows 

 between 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 veinlets. 



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



