89. POLYPODIACE^:. 211 



blunt, completely covered on the back with brown membranous 

 scales concealing the sori. 



Very rare. On old walls. (E) 4 10. Near Paisley. 



8. PT^RIS. Brake. 



P. AQUILINA, L. The Common Brake. Bracken. Rhizome 

 extensively creeping, hard and black. Fronds 1 3 ft. high, in 

 rich soils reaching 8 ft., bi-tripinnate, decreasing in successive 

 branchings, downy beneath; secondary pinnse linear-lanceolate, 

 lower ones pinnatifid, upper entire ; fertile pinnules broad. In- 

 dusium double, marginal. Plant very hard and harsh to the 

 touch. 



Very common. Woods, thickets, and heaths. (B) P. 78. 



9. BL^CHNUM. Hard-fern. 



B. BOREALE, Sw. Northern Hard-fern. Fronds tufted, 12 18 

 in. high. Barren ones exterior and spreading, pinnatifid, seg- 

 ments lanceolate, obtuse. Fertile fronds central, erect, widely- 

 pinnate, segments linear, acute, margin rolled back; sometimes a 

 few intermediate fronds are found, with 2 apparently fertile lines 

 between the midrib and the edge of the segments. 



Common. Woods and heaths. (B) P. 7 8. Cathkin hills ; Cadder wilderness; 

 woods at Garscube, &c. 



10. TRICHOMANES. Bristle-fern. 



T. RADIO ANS, Sw. Rooting Bristle-fern. Rhizome creeping 

 over rocks in the spray of cascades in mountainous countries. 

 Fronds 6 8 in. high, broadly ovate in outline, 3 4 times pin- 

 natifid, segments linear, membranous, quite smooth, more or less 

 toothed, narrowed at the base. The rachis everywhere winged 

 with a narrow membranous margin. Fructification marginal, 

 solitary, in the axils of the small ultimate lobes, cylindrical, with 

 a protruded bristle receptacle. Plant pellucid. 



This very elegant fern was discovered in Arran by Mr. George Combe in 1863. 

 A very questionable native. (P) 6 9. 



11. HYMENOPHYLLUM. Filmy-fern. 



1. TT TtJNBRiDGEisrsE, Sm. Turibridge Filmy-fern. Rhizome 

 creeping, filiform, branched, forming entangled masses, clinging 

 to the surface of rocks. Fronds slender, delicate, membranous, 

 and pellucid, 3 4 in. high, usually oblong or ovate -lanceolate, 



? innate; pinnae flat; segments linear, decurrent on all parts of the 

 rond, forming a wing to the rachis, spinosely serrate. Involucre 

 sessile in the axils of the pinnse, obtuse, spinoso-serrate. 



Frequent. Moist shady rocks. (A) P. 67. "Near Milngavie," Mr. George 

 Thomson; below Gourock; Inverldp glen; banks of Loch Lomond at Luss and 

 Tarbet; Puck's glen above Rashfleld on the Holy Loch; Dunocn; Bute and 

 Arran. 



