Blechnum.] FILICES. 343 



there is a current of damp air. Fronds numerous, tufted, erect, twelve 

 to eighteen inches or more high, sometimes forked at the^summit, or 

 variously crisped or cut at the edges. 



7. PTERIS. Linn. Brake. 



Sort continuous, linear, marginal. Involucres formed of the 

 inflexed margins of the frond, frequently dilated into a mem- 

 brane, opening internally. Name, Tnepis, in Greek, a Fern : 

 from 7rTcpvg, a plume or feather. 



1. P. aquilina, Linn. Common Brake. Fronds tripartite; 

 branches bipinnate ; pinnules linear-lanceolate ; superior undi- 

 vided, inferior pinnatifid, the segments oblong, obtuse. Br. Fl. 

 ed. 3. p. 454. E. Fl. v. iv. p. 318. E. Bot. t. 1679. 



Woods, heaths, and stony or sandy soils, abundant. Employed as 

 litter for cattle. The ashes are useful in the manufacture of soap and 

 glass. The main stalk, when cut across, exhibits in the pith a branched 

 appearance, resembling a spread-eagle, whence the Latin name (aaiii- 

 lina.) 



8. CRYPTOGRAMMA. Br. Rock-brake. 



Sori linear or roundish, oblique, inserted upon the lateral 

 nerves of the pinnule, at length confluent, and thus appearing 

 marginal. Common Involucre formed by the revolute mar- 

 gins of the pinnules, which in a young state meet at the 

 back : partial none. Name ; KpvTrTos, concealed, and ypa/tifiij, 

 a line ; from the concealed lines of the capsules. 



1. C. crispa, Br. Curled Rock-brake. Sterile fronds bi- 

 pinnate ; pinnules bi-tripinnatifid ; segments linear-oblong, often 

 bidentate at the extremity ; fertile fronds bipinnate, tripinnate 

 below ; pinnules linear-oblong, rather obtuse, entire, narrow at 

 the base. Br. Fl. ed. 3. p. 454. Pteris crispa, Linn.E. Bot. 

 t. 1160. E. Fl. v.\v. p. 319. 



Among loose stones in mountainous countries in the north. Abun- 

 dant on the Mourne Mountains. 



9. BLECHNUM. Linn. Hard-fern. 



Sori linear, longitudinal, contiguous, parallel, one on each side 

 of the rib. Involucre superficial, continuous, opening inte- 

 riorly. Name, y3X?/Kj>oi/, another Greek name for a fern. 



1. B. boreale, Sw. Northern Hard-fern. Sterile fronds 

 pectinato-pihnatifid, the segments lanceolate, rather obtuse ; 

 fertile fronds pinnate ; pinnae linear, acuminate. Br. Fl. ed. 3. 

 p. 455. E. Fl. v. iv. p. 316. E. Bot. t. 1159. 



Woods and heaths abundant, especially in a poor light soil. 



