FILICES. 



463 



Swamps. Can. to Flor. ; rather rare. Aug. Q. Fern 1 2 feet high, grow- 

 ing in tufts, smooth except at the lower part of the stipe. Frond lanceolate, 

 tapering at the top ; the veins of the sterile one much reticulated. Sori 3 4 

 lines long, at length nearly covering the back of the pinnae. Indusium involute. 



Narrow-leaved Woodwardia. 



2. W. Virginica Sicartz ; sterile and fertile fronds similar, very smooth, 

 pinnate ; pinnae sessile, lanceolate, pinnatifid. W. lia.nisteriana Mich. 

 Doodia Virginica JPresL 



Swamps. N. Y. and Mass, to Geor. July. '4- Fern about 2 feet high, 

 growing in tufts, smooth. Stipe brown. Frond oblong-lanceolate in its outline, 

 light green, with the segments rather obtuse and a little incurved. Sori in in- 

 terrupted double lines near the midrib of the pinnae and segments. Indusium 

 revolute. Virginian Woodwardia. 



10. PTERIS. Linn. Brake. 

 (From the Greek irrer,v, a plume or feather ; in allusion to the form of the frond.) 



Sori marginal, linear, continuous or interrupted, forming a 

 transverse receptacle which connects the apices of the veinlets. 

 Indusium linear, narrow, occupying the margin of the frond ; 

 the inner side free. 



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

 linear-lanceolate, lower pinnatifid, upper undivided ; segments oblong, ob- 

 tuse. P. cor data Pnrsh. 



Dry woods. Can. to Flor. July, Aug. Ij.. Stipe I 2 feet long, angular, 

 smooth, light brown, divided into large opposite branches. Frond 12 or 3 feet 

 in diameter, bi-triternately divided, spreading, dull green ; some of the pinnules 

 with only a single lobe, and appearing auricled. Sori uninterrupted, resembling 

 a thickened russet edging. One of our largest ferns. Common Brake. 



2. P. atropurpurea Linn. : frond pinnate or subbipinnate ; lower divisions 

 ternate or pinnate ; segments lance-oblong, obtuse, entire, obliquely trun- 

 cate or subcordate at base. Platyloma airopurpurea J. Smith. 



On rocks. N. Y. to Car. July. %. Stipe, 2 4 inches long, dark purple, 

 terete, slender, roughish-pubescent. Frond 4- 8 inches long, grayish-green. 

 Sori conspicuous, linear and marginal. Indusium membranaceous, often undu- 

 lately crenate. Purple-stalked Brake. 



3. P. gradlis Mich. : frond lanceolate ; the sterile pinnate, with pinna- 

 tifid divisions and a few broad-ovate obtuse segments ; the fertile bipinnate, 

 with linear-oblong acute slightly crenate segments. Cheilantkes gracilis 

 Spreng. AUosurus gracilis J. Smith. 



Moist rocks. Can. and N. Y. ; rare. Aug. r l\.. Stipe 1 3 inches long, 

 dark brown and shining. Frond 2 4 inches long, smooth, membranaceous. 

 Sori approximated. Indusium membranaceous. Smaller and more delicate 

 than the preceding. Abundant on the rocks near Whitehall, N. Y. 



Slender Brakf. 



11. ADIANTUM. Linn. Maiden Hair. 

 (From the Greek aXeaj/roj, dry ; its surface repelling moisture.) 



Sori oblong or roundish, marginal. Indusium membranaceous, 

 arising from the reflexed margin of distinct segments pf the 

 frond, opening along the lower or inner side. 



