FILICES. (FERNS.) 681 



base ; involucres lunulate 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 reflexed 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 TTTepbv, a wing, 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 the lobes very narrow and revolute, the terminal ones much elongated, 

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

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



5. CHEILANTHES, Swartz. LIP-FERN. (PL 17.) 



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 lobes 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 x ^ os > a Mp> an( i Mos, flower, from the shape of the in- 

 dusium.) 



* Fronds smooth, or at most hairy. 



1. C. Alabam&nsis, Kunze. Fronds smooth, chartaceous (2-8' long), 

 ovate-lanceolate, bipinnate ; 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 promi- 

 nently articulated rusty hairs, twice pinnate ; pinnae rather distant, triangular- 

 ovate; pinnules oblong, crowded (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. Denslow) and N. J. to 111., and southward. 



* * Fronds woolly or tomentose. 



3. C. toment6sa, Link. Fronds (12-20' high) lanceolate-oblong, densely 

 tomentose with slender and entangled whitish obscurely articulated hairs, thrice 

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

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

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



