RADULA. 69 



ascending. Leaves imbricate, patent-divergent, 70°, unequally 

 bilobed, antical lobe plane or slightly convex, crossing the stem, 

 subrotund or broadly obovate, margin quite entire or erose by 

 formation of gemmse, postical lobe 3 to 4 times smaller, appressed 

 to the antical lobe, quadrate, free angle acute, inner margin 

 reaching to the middle of the stem, upper angle rotundate or 

 acute ; cells smallish to medium in size, hexagonal, walls firm, 

 no trigones or thickened angles. Bracts unequally bilobed, 

 antical lobe obovate-elongate, postical lobe about one-third smaller, 

 oblong-quadrate, free angle acute or obtuse. Perianth projecting 

 to about the middle beyond the bracts, obovate, complanate, trun- 

 cate. Capsule brown, dividing into 4 longish oval valves, elaters 

 usually monospiral ; spores roundish. Androecia terminal on the 

 chief stem or on long lateral branches ; perigonial bracts closely 

 imbricate, bilobed, turgid at the base, antical lobe oval, apex rotun- 

 date, postical slightly shorter, oval, apex obtuse ; antheridia spheri- 

 cal. Gemmse often abundant at the margin of the upper leaves. 



Dimensions. — Stems 1 to 2 inches long, with leaves 2" to 3* 

 mm. wide, diam. of stem "15 mm. ; leaves, antical lobe TS mm. x 

 1'25 mm., postical lobe 75 mm. x "6 mm., antical 1'25 mm. x 

 1* mm., postical "6 mm. x '5 mm., antical 1*2 mm. x '8 mm., postical 

 •6 mm. x '4 mm. ; cells '0225 mm. x '0225 mm., '03 mm. x '03 

 mm., '0225 mm. x '03 mm. ; bracts, antical lobe 1-25 mm. x 75 

 mm., postical lobe 75 mm. x '5 mm.; perianth 2*25 mm, x 1*1 

 mm. ; elaters '3 mm. x "006 mm. ; spores "03 mm. 



Hab. — In spreading flat patches, closely attached to damp 

 rocks in exposed or shaded situations, usually in hilly or subalpine 

 localities. Eare. 



2. New Forest, C. Lyell, 1813, March 12, 1814. 7. Clogwyn- 

 du-Arddu, Snowdon, Carnarvonshire, W. H. P. 12. Harter Fell, 

 and Mardale, Westmorland, G. Stabler. Near Keswick, Dr. 

 Carrington and W. H. P. 15. Braemar, A. Croall. 



Found on the Continent and in Canada (rocks near Belleville), 

 Macoun. 



Obs. — Distinguished from R. complanata (L.) by its dioicous 

 inflorescence; from R. aquilegia, Tayl., by its colour, and the 



