Q'Z4: FLORA OF TEXAS. 



155. FERN FAMILY. Order, Filices. 



Stem a creeping horizontal rhizoma, sometimes erect and 

 arborescent; leaves (fronds) variously divided, circinate 

 vernation, and raised on a foot-stalk or stipe; fructification 

 borne on the back or margin of the fronds; ^/jore-case 

 sometimes covered by a membrane, called the indusium or 

 involucre^ and containing numerous minute spores or seeds. 



POLYPODIUM, L. Polypody. 



Fruit-dots round, naked, mostly at the ends of the free 

 or reticulated veins ; rootstocJcs creeping ; sterile and fertile 

 fronds alike. 



§ 1. PoLYPODiuji proper. Veins free. 



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, etc., in shady woods. Fronds 4-10' high. 



§2. Marginaria, Bory, Veins obscure, sometimes reticulating near the margin; 

 stipe and lower surface of the frond covered with chaffy scales. 



P. iiTCAKUM, Swartz. Fronds evergreen, coriaceous, be- 

 neath thickly beset with peltate chaffy scales, smooth and 

 green above, pinnately parted; the divisions oblong, ob- 

 tuse, entire ; fruit-dots near the margin. On trunks of 

 trees. Rootstock chaffy, creeping ; fronds 3-8' high. 



PTEEIS, L. 



Sporangia borne on a transverse marginal receptacle 

 connecting the ends of the veins; ind^isium continuous, 

 formed of the membranaceous marofin of the frond, at first 

 reflexed, at length pushed back and disclosing the ripened 

 fructification ; fronds 1-3-pinnate or decompound. 



P. AQUILINA, L. (Brake.) Fronds large, glabrous or 



