POLYPODIACEAE (FERN FAMILY) 37 



fronds (8-17 cm. high) ovate-lanceolate, woolly with soft whitish distinctly 

 articulated flattened hairs, becoming smoother above, twice or thrice pinnate; 

 pinnae (8-12 mm. long) ovate, the lowest distant, the others contiguous ; pin- 

 nules crenately pinnatifid, or mostly divided into minute and roundish densely 

 crowded segments (1-2 mm. long), the herbaceous margin recurved and forming 

 an almost continuous indusium. (C. lanuginosa Nutt.) In dense tufts, on 

 dry rocks and cliffs, 111. to Minn., thence w. and south w. 



7. PELLAEA Link. CLIFF BRAKE 



Sporangia in roundish or elongated clusters on the upper part of the free 

 veins, distinct, or confluent laterally so as to imitate the marginal continuous 

 line of fructification of Pteris, commonly covered by a broad membranaceous and 

 continuous (rarely interrupted) general indusium, which consists of the reflexed 

 and altered margin of the fertile pinnule or division. Small ferns, with 1-3- 

 pinnate fronds, the fertile ones with narrower divisions than the sterile, but 

 otherwise similar. Stipes generally dark-colored, smooth, and shining. (Name 

 from 7reXX6s, dusky, alluding to the stipe.) 



1. P. atropurpurea (L.) Link. Smooth, except some bristly-chaffy hairs on 

 the midribs and especially on the dark purple and polished stalk and rhachis, 

 1-6 dm. high ; fronds coriaceous, pale, once or below twice pinnate ; the divi- 

 sions broadly linear or oblong, or the sterile sometimes oval, chiefly entire, some- 

 what heart-shaped or else truncate at the stalked base ; veins about twice forked. 

 Dry calcareous rocks, "N. H." and Vt. to R. I., Ga., and westw. ; not common. 

 July. Var. CRISTATA Trel. is a form with dichotomously forked pinnae, somewhat 

 crowded toward the summit of the frond. Eureka, Mo. (G. Pauls}. 









s 



: 



8. CRYPTOGRAMMA R. Br. ROCK BRAKE 



Fruit dots roundish or elongated and extending far down on the free forking 

 ems. Margins of the fertile segments herbaceous or more or less scarious, at 

 first reflexed and meeting at the midrib, at length opening out flat and exposing 

 the confluent sporangia. Low ferns, with smooth 2-3-pinnate tufted fronds, 

 the fertile ones taller than the sterile, and with narrower divisions. (Name 

 from KpvTTTbs, hidden, and ypa^^-f), a line, alluding to the lines of sporangia 

 at first concealed by the reflexed margin.) 



* Revolute margins of the fertile frond bearing a distinct scarious indusial 

 border; ultimate segments of the sterile fronds lance-linear, acute. 



1. C. de"nsa (Brack.) Diels. Fronds not very dissimilar, 8-20 cm. high ; 

 stipes purplish brown ; segments of the sterile fronds lance-linear, very acute, 

 incisely serrate. (Pellaea Hook.) Calcareous or serpentine walls of ravines, 

 etc., Mt. Albert, Gaspe" Co., Que. ; Grey Co., Ont. ; and in the far west. 



* Rf volute margins of the fertile frond scarcely modified; ultimate segments 

 of the sterile fronds broader. 



2. C. acrostichoides R. Br. Fronds markedly dissimilar ; segments of the 

 ertile linear (6-10 mm. long), of the sterile ovate-oblong, obtuse, serrulate ; 



stipes straw-colored, scaly especially toward the base. Crevices of rocks, 

 Arctic Am. to L. Huron, L. Superior, Col., and Cal. 



3. C. Stelleri (Gmel.) Prantl. Fronds markedly dissimilar; segments of 

 e fertile linear-oblong to lance-linear; those of the sterile ovate to obovate- 



nabelliform, crenulate, decurrent at their cuneate bases. (Pellaea gracilis 

 Hook.) Shaded chiefly calcareous rocks, Que. and N. B. to Vt., Ct., n. Pa., 111., 

 and north westw. ; local. (Asia.) 





9. WOODWARDIA Sm. CHAIN FERN 



Fruit dots oblong or linear, arranged in one or more chain-like rows on trans- 

 verse anastomosing veinlets parallel and near to the midrib. Indusium fixed by 





