F'iUCES. (ferns.) 681 



l)ase , involucres luuulate or transversely oblong. — Moist rocky places, Va. 

 to Mo., and southward. (Eu.) 



4. PTERIS, L. Brake or Bracken. (PI. 17.) 



Sporangia in a continuous slender line of fructification, occupying the entire 

 margin of the fertile frond, and covered by its retiexed narrow edge which 

 forms a continuous membranaceous indusium, attached to an uninterrupted 

 transverse vein-like receptacle connecting the tips of the forked free veins. — ■- 

 Fronds 1-3-pinnate or decompound. (The ancient Greek name of Ferns, 

 from TTTepov, a icing, on account of the prevalent pinnate or feathery fronds.) 



1. P. aquilina, L. (Common Brake.) Frond dull green (2-3° wide), 

 ternate at the summit of an erect stout stalk (1 -2° high), the widely spread- 

 ing branches twice pinnate; pinnules oblong-lanceolate ; the upper undivided; 

 the lower more or less pinnatifid, with oblong obtuse lobes, margined all round 

 with the indusium, which is really double in this species. — Var. caudata, 

 with f\\e. lobes very narrow and revolute, the terminal ones m.uch elongated, 

 is a southern form, w hich extends in a modified condition as far north as New 

 Jersey. — Thickets and hillsides, common. Aug. (Eu.) 



5. CHEILANTHES, Swartz. Lip-Fern. (PI. 1 7.) 



Sporangia borne on the thickened ends of free veinlets, forming small and 

 roundish distinct or nearly contiguous marginal fruit-dots, covered by a mostly 

 whitish and membranaceous, sometimes herbaceous, common indusium, formed 

 of the reflexed margin of separate lol)es or of the whole pinnule. — Low, mostly 

 with 2-3-pinnate and hairy or chaffy, rarely smooth fronds, the sterile and 

 fertile nearly alike, the divisions with the principal vein central. Some spe- 

 cies with continuous indusium connect this genus very closely with the next. 

 (Name composed of xeTAos, a lip, and &uGos. flower, from the shape of the in- 

 dusium.) 



* Fronds smooth, or at most hairy. 



1. C. Alabamensis, Kunze. i^ronc/i; smoo^A, chartaceous (2-8' long), 

 ovate-lanceolate, bipinuate ; pinnae numerous, oblong-lanceolate ; pinnules tri- 

 angular-oblong, rather acute, often auriculate or lobed ; indusium continuous, 

 rather broad, pale, and of firm, consistence. — On rocks, mountains of Va. to 

 Ky., and southward. 



2. C. vestita, Swartz. (PI. 17, fig. 1, 2.) Fronds (6-15' high), lanceo= 

 late-oblong, hirsute, as are the brown and shining stipes, with straightish jyromi- 

 nentlij articulated rusti/ hairs, twice pinnate; pinnte rather distant, triangular- 

 ovate ; pinnules oblong, croAvded (2 - 4" long), more or less incised, the ends 

 of the roundish or oblong lobes reflexed and forming separate herbaceous involucres. 

 which are pushed back by the ripened sporangia. — Clefts of rocks, Manhattan 

 Island ( W. W. Densloiv) and N. J. to 111., and southward. 



* * Fronds woollg or tomentosQ. 



3. C. tomentbsa, Link. Fronds (12-20' high) lanceolate-oblong, densely 

 tomentose with slender and entangled whitish obscure Ig articidated hairs, thrice 

 pinnate; primary and secondary pinnae oblong or ovate-oblong; pinnules dis- 

 tinct, mmnte (i-1'' long), roundish-obovate, sessile or adnate-decurrent, the 

 upper surface less wooWv, the reflexed narrow margin forming a continuous some- 



