FILICES. 455 



HAB. On rocks. Can. and N. S. Aug. 1(. Smaller and of a 

 much more delicate habit than the last. Frond with the stipe, 

 46 inches high, smooth and shining. Specimens of thi 

 plant which I found in abundance on the rocks near Whitehall,- 

 N. Y., were collated by Dr. Hooker and determined to be the 

 true P. gracilis, and he also remarks that he cannot comprehend 

 why Kaulfuss and Sprengel should make it a Cheilanthes. 



3. P. aquilina Linn. : frond 3-parted ; branches bipinnate ; pinnse 

 linear-lanceolate, lower ones pinnatifid, upper ones undivided ; seg- 

 ments oblong, obtuse. 



HAB. Dry woods. Can. to Flor. July. U> Fern 2. 6 feet 

 high, according to the soil. Stipe angular, dark coloured and 

 polished, dividing into large opposite branches. Frond very 

 large, pale green. Dr. Hooker thinks that the plant which 

 passes under this name among our botanists is the next. 



4. P. caudata Linn. : frond pinnately 3-parted ; sterile divisions bi- 

 pinnate, with the segments linear, long, obtuse, and very entire ; fer- 

 tile divisions pinnate ; segments rather remote, the lower ones pinhati- 

 fid, dentate at the bas,e. 



HAB. Rocky woods near streams. Penn. to Car. Pursk. Aug. 

 If Dr. Hooker's opinion is correct, this species is very common 

 in the N. S. 



9. ADIANTUM. Linn. 



Sort oblong or roundish, marginal. Involucre membran- 

 aceous, arising from distinct portions of the frond turned in, 

 opening inwards. 



A. pedatum Linn. : frond pedate ; divisions pinnate ; pinnae oblong, 

 somewhat lunate, with the upper margin incised; sori linear, stipe 

 smooth. 



HAB. Shady woods. Can. to Vir. Louis. Raf. July. 1(. 

 Fern 1 2 feet high, easily know'n by its long slender black and 

 highly polished st ipe, and its pedate nearly horizontal frond* 



10. CHEILANTHES. Sioartz. 



Sori roundish, distinct, situated at the margin of the frond. 

 Involucre of membranous distinct inflexed scales, opening in- 

 wards. 



C. vcstita W'dld. : frond bipinnate, hairy on both sides ; pinnule* 

 pinnatifid ; segments rounded, oblong, very entire ; stipe and rachis 

 hairy. 



HAB. Rocks. Penn. to Car. W. to Rocky Mountains. July. 

 K. Fern 68 inches high, and covered with long brownish 

 hair. Sori at length contiguous. 



11. HYMENOPHYLLUM. Smith. 



Sari in separate spots at the margin of the frond. Capsules 

 sessile, inserted on a common cylindrical receptacle, within a 



