Page:Journal of botany, British and foreign, Volume 34 (1896).djvu/265

 241 A NEW HEPATIC. By W. H. Pearson. (Plate 358.) Plagiochila Stabler!, n. sp. Dioicous, loosely caespitose, small, pale to brownish green in colour. Stems creeping, simple or irre- gularly branched; branches ascending, radiculose ; rootlets few, single, white. Leaves imbricate or distant, bifarious, alternate, horizontal or patent-divergent, largest near the middle of the stem, very slightly or not at all decurrent antically, plane or slightly concave, oblong-quadrate, oval or subcuneate, bidentate to about one-fourth, retuse or entire, margin quite entire; texture somewhat thick ; cells from moderate to largish in size, roundish-quadrate ; walls thick, angles thickened. Stipules evident, simple or bifid, segments subulate. Dimensions. Stems ^ in. long, with leaves 1-25 mm. wide; diameter of stem 0*15 mm. ; leaves 0*7 X 0*5 mm., 0*5 x 0*5 mm., 0-7 X 0-45 mm. ; segments 0*2 mm., 0-6 x 0-5 mm., 0*7 X 0-55 mm. ; segments 0*1 mm. ; cells 0*04 x 0-045 mm., 0-04 x 0-04 mm., 0-035 X 0-04 mm., 0-035 x 0-035 mm. ; stipules 0-225 x 005 mm., 0-2 x 0-08 mm., 0-2 x 0-04 mm. Hah. On rocks near Fall, Rydal Park, Rydal, Westmoreland, Mr, George Stabler, Sept. 1877. Obs. Although the small flagelliferous varieties of P. spinulosa (Dicks.) and P. punctata Tayl. are numerous, P. Stableri cannot be confounded with any of them, the almost horizontal insertion of the bidentate, retuse or entire leaves, which are nearly plane, and their much larger cells at once distinguish the species. P. tridenticulata Tayl., which has usually bidentate leaves, oblong-oval in shape, with a very narrow base and small cells, is very distinct. P. exlgua Tayl. has very decurrent leaves of a different shape, with an extremely narrow base ; cells much smaller. Leptoscyphus interriiptiis (Nees), with which it agrees somewhat, in the insertion of its leaves, is a much more robust plant, with usually entire leaves and less evident stipules. Description of Plate 358. — Fig. 1. Plants, natural size. 2. Plant, antical view, X 24. 3-8. Leaves, x 31. 9. Portion of leaf, x 290. 10-12. Stipules, X85. JoTJRNAi, OP Botany. — ^Vol. 34. [June, 1896.]