Pteris. FILICES. 341 



Clefts of rocks in the Sierra Nevada, mostly at from 6,000 to 9,000 feet elevation. The under 

 surface of the frond sometimes bears a trace of the same yellowish waxy powder seen in many 

 species of Gijinnogramme and Notkolccna. 



P. FLEXiiosA, with flexuous rliachis and rather large cordate-ovate pinnules occurs in Arizona, 

 and may yet be discovered in the southern part of California. P. gracilis and P. alropurpurca 

 are well-known species of the Eastern States. 



6. CRYPTO GRAM ME, R. Brown. Rock-Br.vke. 



Sporangia on the back or near the end.s of the free veins, forming oblong or 

 roundish, and at length confluent sori : involucres continuous, formed of the mem- 

 branaceous and somewhat altered margins of the pinnules, at first reflexed and meet- 

 ing at the midrib, at length opening out flat. Fronds rather small, herljacecjus, 

 smooth, dimorphous, 2 - 4-pinnate, the fertile ones taller than the sterile, and with 

 narrowly elliptical or oblong-linear pod-like segments. Stalks stramineous, tufted on 

 a short rootstock. 



A genus of only two species, C. crispa of Europe, and the following. 



1. C. acrostichoides, E. Brown. Eootstocks short, creeping, chaffy: stalks 

 densely clustered : fnuids chartaceous, ovate, 2 - 3-pinnate, 2 to 4 inches long ; 

 sterile ones sh(jrt-stalked, having narrowly winged rhachises, ultimate segments 

 crowded, ovate or obovate, adnate-decurrent, crenately toothed or slightly incised ; 

 fertile fronds long-stalked, the rhachises scarcely winged, ultimate segments oblong 

 or linear-oblong, 3 to 5 lines long, scarcely one line wide ; involucres very broad : 

 sori oblong, extending down the forked veinlets almost to the mid vein. — Hooker 

 & Greville, Ic. Fil. \, t. 29; Eaton, Ferns of K Amer. ii. 99, t. 59, fig. 1-5; 

 Williamson, Fern Etchings, t. 7. Allosorus acrostichoides, Sprengel ; Gray, Manual. 



Common among rocks at high elevations, extending to Colorado, Lake Superior, the Aleutian 

 Islands and Arctic America. The fronds are more rigid and less compound than in C. crispa, and 

 the sporangia are not limited to the upper part of the veins, as they are in that sj^ecies. But sev- 

 eral able botanists consider the two as forming but one species. 



7. PTERIS, Linn. Bracken. 

 Sporangia seated on a continuous vein-like marginal receptacle, which connects 

 the ends of the veins : involucre extending around the margins of the segments, or 

 sometimes interrupted at their apices, and sometimes double. Fronds, in the only 

 Californian species, ample and decompound, the veins free. 



A large genus, having many tropical species, with fronds varying from simple to decompound, 

 the veins free or variously reticulated. Stalks commonly light-colored. 



1. P. aquilina, Linn. Rootstock blackish, cord-like, creeping widely under- 

 ground : .stalks solitary, erect, naked, swollen and discolored at the base : frond 

 sometimes 3 feet long and nearly as broad, rigidly subcoriaceous, smooth or pubes- 

 cent, triangular-ovate" in outline, 2 -4-pinnate at the base; principal primary pinme 

 stalked, the lowest ones very large, the rest rapidly becoming smaller ; pinnules 

 oblong-lanceolate or linear, entire, hastate, or pinnately parted ; segments oljlong or 

 linear, obtuse, the terminal ones often elongated ; veins close-placed, free, repeatedly 

 forking. — Eaton, Ferns of K Amer. i. 263, t. 35 ; Williamson, Fern Etchings, t. 10. 



Var^ lanuginosa, Bong. Lower surface of the frond decidedly pubescent or 

 silky-tomentose, the segments broad. — Veg. Sitch. 176. 



Very common throughout the State, extending northward to Sitka and eastward to Utah. In 

 Northern California and Oregon it forms thickets six or seven feet high and several acires in ex- 

 tent. The plant of the Eastern States is less pubescent or nearly smooth. Tlie bracken is tlie 

 most widely distributed of all ferns, and in many i)arts of the world either tlie young fronds, when 

 boik'd, or the rootstocks after roasting, have served as articles of food. Tlie mature fronds have 

 been used for thalLhing, and tlie ashes for scouring or lor making domestic so;ip. 



