26 



POLYPODIACEAE 



part of the peninsula, \vhere it occurs as far north as 

 the northern part of the lake region. It grows naturally 

 in Texas and is common in insular and continental 

 tropical America. 



11. DRYOPTERIS Adans. 



Coarse or delicate terrestrial wood- ferns. Leaves 

 erect, spreading, or creeping, usually clustered on the 

 rootstock, the petiole not jointed to the rootstock: blades 

 narrow or broad, 1- to 3-pinnate, or dissected; leaflets 

 usually toothed or lobed. Veins simple or forked, free or 

 variously jointed. Sori nearly or quite orbicular, borne 

 on the back of the leaf-blade or its divisions, on the 

 veins or rarely at their 

 tips. Indusia orbicular-reni- 

 form, attached at the center 

 or at or near the sinus, or 

 vestigial in a few species. 

 Several hundred species of 

 wide geographic distribu- 

 tion, chiefly tropical. 



1. D. patens (Sw.)Kuntze. 

 Eootstock stout, erect or 

 nearly so: leaves clustered, 

 arching, 1.5 m. long or less; 

 petioles sparingly scaly near 

 the base: blades ovate in 

 outline, sometimes narrowly 

 so, or lanceolate, usually 4-8 

 dm. long, more or less pubes- 

 cent, often sparingly so, acu- 

 minate, 1-pinnate ; leaflets 

 numerous, often very numer- 

 ous, approximate, mostly 9- 

 20 cm. long, the blades lin- 

 ear-acuminate, sessile, pin- 

 natifid, spreading or the 



