90 OUR NATIVE FERNS AND THEIR ALLIES. 



3. A. Jordan! C. Muell. Stipes rather stout, nearly black, 

 polished; fronds ovate or deltoid-pyramidal, bi — tripinnate; 

 pinnules and upper pinnse ample, smooth, or nearly so, rounded 

 or even reniform, upper margin rounded, slightly incised ; sori 

 2— S, transversely linear-oblong, subcontinuous. (A. emargina- 

 ium of former edition not Hook.) 



tt Fronds pilose, with whitish hairs. 



4. A. tricholepis Fee. Stipes smooth, polished, deep 

 black ; fronds oval ; pinnules roundish, moderately long-stalked ; 

 sori few (3—7), of unequal size; indusia very velvety. (A. 

 dilatatum Nutt.) Western Texas. 



** Fronds dichotomousfy forked, with numerous pinnce spring- 

 ing from the upper side of the two branches. 



5. A. pedatum L. Stipes 9' — 15' long, dark chestnut- 

 brown, glabrous ; fronds nearly circular in outline ; central pin- 

 nae 6'— 9' long, i' — 2' broad; pinnules triangular-oblong, short- 

 stalked ; sori roundish or transversely oblong. North Carolina 

 to California and northward. 



Var. rangiferinum Burgess. Pinnules longer-stalked and 

 deeply cleft into narrow-toothed lobes on the upper side. Mount 

 Findlayson, British Columbia. 



XI. PTERIS L. Brake. 



Sori marginal, linear, continuous, occupymg a slender fili- 

 form receptacle which connects the tips of the free veins. In- 

 dusium membranous, formed of the refiexed margin of the 

 frond. Name from Gr. itripii, a fern, from nrepov, a wing, al- 

 luding to the prevalence of pinnate fronds. A cosmopolitan 

 genus containing sixty or more species as now limited. 

 * Lower pijincB linear, undivided. 

 I. P. longfifolia L. Stipes 6' — 12' long, clothed more or less 

 below with pale-brown scales; fronds i" — 2° long, 4' — 9' broad, 

 oblong-lanceolate; pinnae sessile, 2" — 5" broad, linear, entire; 

 veins close and fine, usually once branched ; indusium yellowish 

 brown. Florida. 



* * Lower pinna forked or slightly pinnate below. 

 2. P. Cretica L. Stipes 6' — 12' long, erect, stramineous 

 or pale-brown ; fronds 6' — 12' long, 4' — 8' broad, lateral pinnas 



