PLAainCHTLA. 273 



1. Plagiochila Stabler!, Penr.so/i. 



Pliujiochila Stahleri, Pears, in Jour, of Bot. June (IH'jo). 



Dioicous, loosely ca3spitose, small, pale to brownish-fifreen in 

 colour. Stems creeping, simple or irre*^ularly branched ; branches 

 ascending; radiculose, rootlets lew, single, white. Leaves imbri- 

 cate 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 slii:;htly concave, oblong-quadrate, 

 oval or subcuneate, bidentate to about one-lburth, 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. 

 DiMKNsioNS. — Stems J inch long, with leaves 1*25 mm. wide; 

 diameter of stem 0'15 mm. ; leaves 0'7 mm. x 0"5 mm., 0*5 mm. 

 X 0*5 mm., 0"7 mm. x 0'45 mm. ; segments 0'2 mm., O'G mm. 

 X 0*5 mm., 07 mm. x 0'55 mm.; segments 0"1 mm.; cells 

 04 mm. X 0-045 mm., 0-04 mm. x 0-04 mm., 0-035 mm. 

 X 0*04 mm., 0*035 mm. x 0*035 mm. ; stipules 0*225 mm. 

 X 0*05 mm., 0*2 mm. x 0*08 mm., 0*2 mm. x 0*04 mm. 



Hab.— On rocks near Fall, Rydal Park, Rydal, Westmorland, 

 Mr. George Stabler, Sept. 1877. 



Obs. — Although the small flagelliferous varieties of P. .yji/ii/Io-sa 

 (Dicks.) and P. jjunctafa, Tayl. are numerous, P. Sfableri 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. f r identic idat a, Tayl., which has usually bidentate leaves, 

 oblong-oval in shape, with a very narrow base and small cells, is 

 very distinct. 



P. eocifjua^ Tayl. has ver}' decurrent leaves of a different shape, 

 with an extremely narrow base ; cells much smaller. 



Pedinophijllnm interruption (Nees), with which it agrees some- 

 what in the insertion of its leaves, is a much more robust ]ilant, 

 with usually entire leaves and less evident stipules. 



s 



