104 OUR NATIVE FERNS AND THEIR ALLIES. 



shorter ; stipes black and polished, as is the lower part of the 

 midrib, especially beneath. Schuylkill River, above Manayunk, 

 Pennsylvania (Scoff) ; Havana, Alabama (Miss Tutwiler) ; 

 Canaan, Connecticut (Adam) ; near Poughkeepsie, New York 

 (Lowri), Jackson County, Illinois (Patterson). 



*** Fronds once pinnate. 

 t Pznnce \' ' long, mostly blunt. 

 \ Rachis chestnut-brown or blackish. 



4. A. platyneuron (L.) Oakes. Stipes 3' 6' long, chest- 

 nut-brown, nearly naked ; fronds 8' 16' long, linear-lanceolate; 

 pinnae 2040, lanceolate, subfalcate, or the lower oblong, \' i 

 long, the dilated base auricled on the upper or both sides ; 

 sori often 1012 on each side. (A. ebeneum Ait., Polypodium 

 platyneuron L.) Florida and Kentucky northward to Canada. 



5. A. parvulum Mart. & Gale. Fronds tufted, erect, 

 rigid, 4' 10' long, narrowly linear-lanceolate ; stipe and rachis 

 black and shining; pinnae numerous, oblong, obtuse, entire or 

 crenulate, auricled on the upper side, nearly sessile ; middle 

 pinnae longest, the lower gradually shorter and deflexed ; sori 

 short. Virginia and Florida to Arkansas and New Mexico. 



6. A. trichomanes L. Stipes densely tufted, purple-brown, 

 shining ; fronds 3' 8' long, ' or more broad, linear ; pinnae 

 15 30 pairs, nearly opposite, roundish-oblong or oval, the two 

 sides unequal, obliquely wedge-truncate at the base, attached 

 by a narrow point, the edge slightly crenate. Eastern United 

 States to the Pacific coast. 



7. A. vespertinum Maxon. Rhizome short; stipes pur- 

 plish-brown, tufted. ' 1 1' long; fronds 3' 9' long; pinnae 

 20 30 pairs, subopposite or alternate, subsessile, oblong-linear 

 or oblong, slightly reduced below, more or less auricled at base, 

 the basal vein once or twice forked ; margins regularly and 

 coarsely crenate-serrate, each lobe containing a simple vein ; 

 sori short, 8 12 to each pinna ; indusium crenate ; spores ovoid 

 with closely reticulated winged ridges. Southern California. 



8. A. monanthemum L. Stipes densely tufted, 3' 6' 

 long, chestnut-brown; fronds 6' 12 long, narrow, with 20 40 

 pinnae on each side ; pinnae crenate above, abruptly narrowed 



