POL YPODIA CE^. 1 1 9 



tate. South bank of Miami River, Florida. March, 1887 

 (Holden). 



XXVIII. FILIX Adans. BLADDER-FERN. 



Sori roundish, borne on the back of the veins. Indusium 

 delicate, hood-like, or arched, attached by a broad base on the 

 inner side partly under the sorus, early opening, free at the 

 other side, and thrown back or withering away. Veins free. 

 Name from Lat. filtx, a fern. (Cystopteris Bernh. and former 

 editions.) Found in the temperate zones of both hemispheres ; 

 contains five species. 



* Fronds ovate-lanceolate, bi tripinnate. 



1. F. bulbifera (L.) Underw. Stipes 4' 6' long; fronds 

 lanceolate, elongate, i 2 long, bi tripinnatifid, pinnae lan- 

 ceolate-oblong ; pinnules crowded, toothed or pinnatifid ; rachis 

 wingless, often bearing bulblets underneath ; indusia short, 

 truncate on the free side. (Asptdium bnlbiferum Swz., Nephro- 

 dimn bulbiferum Michx.) New England to Virginia and North 

 Carolina. 



2. F. fragilis (L.) Underw. Fronds oblong-lanceolate, 

 4' 8' long, i' 2f broad, bi tripinnate; pinnae and pinnules 

 lanceolate or ovate in outline, decurrent along the margined or 

 winged rachis ; indusia tapering or acute at the free end. Nar- 

 rower, less divided specimens, barely bipinnate with obtuse and 

 bluntly toothed pinnules form the var, dentata Hook. Like 

 many other so-called varieties it passes insensibly into the typ- 

 ical form. (Aspidium tenue Swz.) New England to Arizona, 

 California, and northward. 



** Fronds deltoid-ovate, tri quadripinnate. 



3. F. montana (Lam.) Underw. Rootstock slender, 

 creeping ; stipes 6' 9' long, slender ; fronds about 6' each way ; 

 lowest pinnae deltoid-lanceolate, much larger than those above, 

 their inferior pinnules i' i^' long; segments cut to the rachis 

 into oblong lobes, deeply and sharply toothed ; son numerous. 

 Colorado (Brandegee), north shore of Lake Superior, Labrador 

 (Butler), Mt. Albert, Gaspe, Quebec, and northward to Alaska. 



