The Ferns of Washington 103 



S. Petiole 2-5 times as long as the leaf-blade; lower side of 



leaflets not hairy. 13. Crypto gram ma. 



SS. Petiole not longer than the leaf-blade; lower side of 



leaflets covered with long brown hairs. 



12. Cheilanthes. 



PP. Plants over 1 foot high, tufted or not. 



T. Leaves not tufted, triangular, 14 feet or less high. 



15. Pteridii m. 

 TT. Leaves tufted, ovate to lanceolate, 4 feet or less high. 

 U. Leaves broadly ovate, widest at base, 10-15 inches high. 



4. Dryopteris. 

 UU. Leaves oblong-lanceolate, narrowed somewhat at base, 

 12-18 inches high. 3. Phegopteris. 



AA. Main leaf-divisions 2 or 3, each again twice divided. 



V. Main leaf-division 3, each regularly bipinnate; leaflets or lobes 

 not or hardly 1 -sided. 

 W. Leaves tufted, yellowish-powdery on the bark; 2 lateral main 



leaf-divisions sessile or nearly so. 10. Ceropteris. 

 WW. Leaves not tufted, not yellowish-powdery on the back; 3 

 main leaf-divisions each distinctly stalked. 

 X. Leaves 8-18 inches high; leaflets not hairy. 



3. Phe<opterjs. 



XX. Leaves 1-14 feet high; leaflets somewhat hairy beneath. 



15. Pteridm M. 



V V. Main leaf-divisions 2, each at once divided into few long branch- 

 like parts bearing each several to many leaflets; leaflets very much 

 1-sided; leaves tufted. 14. Axhantim. 



Key to the GsNXBA — Basid on the Soki 



(See also page 101) 



A. Indusium present, sori covered. 



B. Sori marginal, covered by modified edge of leaf (false indusium). 



C. Leaves all alike. 



D. Indusium continuous around margin or usually so; sporangia 

 borne on leaf under false Indusium; leaflets more or less 

 bilaterally symmetrical. 

 E. Leaves small, tufted; sori on terminal veins. 



F. Leaves 1 -pinnate; indusium membranous. 11. Pellaea. 



FF. Leaves 2-3-pinnate. 



G. Sterile leaflets brown-hairy; indusium not membranous. 



12. Cheilanthes. 



GG. Sterile leaflets not hairy; indusium membranous. 



13. ("hyptochamma. 



EE. Leaves large, not tufted; sori on continuous veins connect- 

 ing lateral veins. l'>. Pteridicm. 

 DD. Indusia not continuous with each other, oblong; sporangia 

 borne on under side of false indusium; leaflets one-sided. 



14. A DI a nt CM. 



CC. Leaves of two kinds, spore-leaves unlike the foliage-leaves; 

 sori oblong or round, confluent at maturity; two sides of leaflets 

 meeting to form indusium when young, later opening out flat, 



13, Crypto gram ma. 



BB. Sori not marginal, not covered by edge of leaf, a true indusium. 

 H. Sori round. 



