POLYPODIACEAE. 



419 



5. PTERIS L. {Pteridium Scop.) 



Large, mostly coarse ferns, gro^ving in open sunny places, "^\'ith variously 

 divided leaves, and marginal linear continuous sori which occupy a slender or 

 filiform receptacle, connecting the tips of free veins. Indusium double, the 

 outer one conspicuous, membranous, formed of the reflexed margin of the leaf, 

 in inner one delicate and obscure. Stipes continuous with the rootstock. 

 [Greek name for ferns, from the fancied resemblance of their leaves to the 

 wings of birds.] A few species of wide distribution. Type species: Pteris 

 aquilina L. 



1. Pteris caudata L. 



Southern Bracken. (Fig. 

 455.) Leaves erect, 3°-6° tall; 

 blades triangular in outline, 

 2-4-pinnate; divisions pinnati- 

 rid, the ultimate segments nar- 

 row, with recurved margins, re- 

 mote from one another, scarcely 

 decurrent on the rachis except 

 near the apex, the larger with 

 1-12 similar but shorter seg- 

 ments. [P. aquilina of Jones 

 and Lefroy; P. aquilina cau- 

 data Hemsley; Pteridium cau- 

 datum Maxon.] 



Abimdant in fresh water 

 marshes, and occurs also in 

 shaded rocky situations between 

 Harrington Sound and Castle 

 Harbor. Native. Florida and 

 the West Indies. 



6. ADIANTUM [Tourn.] L. 



Graceful ferns of rocky hillsides, woods, and ravines, with much divided 

 leaves and short marginal sori borne on the under .side of the reflexed and 

 altered portion of the pinnule, which serves as an indusium. Stipes and 

 branches of the leaves slender or filiform, often polished and shining. [Name 

 ancient.] A genus of over 175 species, mostly of tropical America. Type 

 species: Adiantum Capillus-Veneris L. 



