FILICES. 463 



Swamps. Can. to Flor. ; rather rare. Aug. %. — 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 pinnse. Indusium involute. 



Narrow-leaved Woodimrdia. 



2. W. Virginica Swartz : sterile and fertile fronds similar, very smooth, 

 pinnate ; pinrwe sessile, lanceolate, pinnatifid. W. Banisteriana Mick. 

 Doodia Virgiiiica Presl. 



Swamps. N. Y. and Mass. to Geor. July. %. — 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 pinnse and segments. Indusimn 

 revolute. Virginian Woodwardia. 



10. PTERIS. /.m?^.— Brake. 

 (From the Greek 7rr£f>«|, a plume or featlicr ; 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. cordata Pursh. 



Dry woods. Can. to Flor. July, Aug. %.— Stipe 1—2 feet long, angular, 

 smooth, light brown, divided into large opposite branches. Frond 1 — 2 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. Plalyioma atropurpurea J. Smith. 



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

 terete, slender, roughish-pubescent. Frond 4—8 inches lon^, grayish-green. 

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

 lately crenate. Purple-stalked Brake. 



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

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

 with linear-oblong acute shghtly crenate segments. Cheilanthes gracilis 

 Spreng. AUosurus gracilis J. Smith. 



Moist rocks. Can. and N. Y. ; rare. Aug. %. — Stipe 1 — 3 inches long, 

 dark brown and shining. Frond 2 — 4 inches long, smooth, membranaceou.*. 

 Sori approximated. Indusium membranaceous. Smaller and more delicate 

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



Slender Brake. 



11. ADIANTUM. Z>m?^.— Maiden Hair. 

 (From the Greek aXiaurdf, dry ; its surface repelling moisture.) 



Sori oblong or roundish, marginal. Indusium membranaceous, 

 arising from the refl^xed margin of distinct segments- of the 

 frond, opening along the lower or inner side. 



