98 OUR NATIVE FERNS AND THEIR ALLIES. 



rachis into a few broad, blunt, slightly-lobed pinnules; texture 

 tliiiily herbaceous, flaccid; indusium broad, continuous, mem- 

 branous; veins of the fertile fronds mostly only once forked. 

 {Allosorus crispus, var. Stelleri Milde, A. gracilis Presl, Pteris 

 gracilis Michx., P. Stelleri Gmelin.) Labrador to Pennsylvania, 

 Illinois, Colorado, and northward. 



§ 2. Allosorus Baker. Texture coriaceous, the veins not 

 perceptible ; indusiwn broad, conspicuous. 



* Pijinulcs or segments obtuse or barely acute. 

 t Fronds pinnate or bipiufiate. 



3. P. atropurpurea (L.) Link. Stipes tufted, 2' — 6' long, 

 dark-purple; fronds 4' — 12' long, 2' — 6' broad, lanceolate or 

 ovate-lanceolate, simply pinnate or bipinnate below ; pinnules 

 and upper pinnae i'— 2' long, \' broad or less, nearly sessile, 

 smooth; indusium formed of the slightly altered incurved edge 

 of the pinnules. {Allosorus atropurpureus ]^\mze, Pteris atro- 

 purpurea L., Platyloina atropurpurea J. Sm.) Arizona, New 

 Mexico, Texas to Vermont and northward. 



4. P. aspera (Hook.) Baker. Stipes slender, 2' — 3' long, 

 with scurfy pubescence , fronds 4'— 6' long, oblong-lanceolate, 

 bipinnate ; pinnae and pinnules deltoid-lanceolate or oblong, 

 pinnules next to main rachis often lobed ; all of them rough o\\ 

 both surfaces with short harsh hairs. {C/ieilanthes aspera Hook.) 

 Western Texas and New Mexico. 



t+ Fronds bi — quadripinnate, ultimate segments oval or cordate. 



5. P. andromedaefolia (Kaulf.) Fee. Stipes scattered, pale- 

 brown, 2' — 12' long; fronds 6' — 12' long, 3' — 6' broad, ovate, 

 l)i — quadripinnate, usually tripinnate ; pinnae rather distant, 

 spreading; ultimate pinnules 2" — 5" long, oval, slightly cordate, 

 coriaceous, the margin of the fertile ones sometimes revolute to 

 the midrib; veins numerous, parallel. {Allosorus andromedce- 

 f alius Kaulf., Pteris andronicdcefolia Kaulf.) California. 



6. P. pulchella (M. et G ) Fee. Stipes tufted, 3' — 8' long, 

 chaffy at base, nearly black ; fronds 3' — 9' long, i' — 5' broad, 

 triangular-ovate, quadripinnate below, gradually simpler above ; 

 lower pinnae deltoid, narrowly triangular above; ultimate pin- 

 nules numerous", i" — 3" long, oval or often cordate-ovate, 

 stalked, coriaceous, smooth, the edges often much reflexed. 



