PLAGIOTHECIUM MULLERIANUM IN BRITAIN. 245 



Plagiothecium Mullerianum Schp. (Synopsis, ed. 1, I860).* 

 Syn. Flag, rostellatum Mol. in Sched. 1861. 



Hypnum Mullerianum Hook, fil., New Zealand Fl. (nomen 



solum), 1867. 

 Isopterijfjium Borrcrl Lindb. Notis. Sallsk. Faun, et Fl. fennica, 



1874. 

 Flag. Molendoi Lorentz in Sched. 



Isoptenjqium Mullerianum Lindb. in Meddel. Soc. Faun, et 

 FlV fennica, 1887. 



Type in Schimper's Herbarium at Kew. 



In loose irregular tufts or patches, pale bright or yellowish 

 green, highly glossy. Stems short, prostrate and often rooting at 

 intervals, irregularly branched in a complanate manner. Branches 

 5-15 mm. long, moderately robust and resembling those of P. 

 Borrerianum, or more frequently slender and similar to those of 

 P. 2)ulchellum. var. nitidulum ; often producing numerous extremely 

 slender small-leaved flagelliform shoots. Stems stout, 150-220 fx or 

 more in thickness, without a distinct central strand ; cortical cells 

 large, lax, thin-walled, usually 16-22 /x in width. 



Leaves rather close, exactly and rigidly comjylanate, so as to 

 appear distichous, usually less widely divergent from the stem 

 than in the allied species ; from a somewhat narrowed not decurrent 

 base ovate-lanceolate, concave, gradually narrowed upwards and 

 then somewhat rapidly long apiculate (in the more slender forms 

 the leaves are narrower, and much more gradually tapering to a 

 fine acumen) ; mdhV gin -plsnae, quite ejit ire ; nerve double, extremely 

 faint and short. Cells very narrow, about thirty times as loug as 

 broad (80-100 /x x 3-5 /x), very little wider towards base and not 

 distinctly enlarged at angles ; at insertion a few very short, irregularly 

 elliptical. 



Dioicous. Male plant with the perigonia small, scattered along 

 the stem. Fertile j)lant with the perichsetia very numerous along 

 the stem and principal branches. Paraphyses numerous, long (in 

 P. pulchellum few and short). Capsule almost erect, or inclined, lid 

 shortly and bluntly rostellate. Fruit ripe in late summer. 



Hab. On the ground, stones, and tree-roots in sheltered spots 

 on mountains. Ben Wyvis, 1867 {Sutherland d McKinlay) ; Ben 

 Narnain, Arrochar, 1896 (Murray) ; Craig Chailleach, near Killin, 

 1897 (Dixon). All female plants, sterile. 



The locality in which I gathered the plant in 1897 was on the 

 shady bank of a deep ravine by a mountain stream on the side of 

 Craig Chailleach, not far from Lochay Bridge, at an unusually low 

 altitude for the species (the range of which is given by Limpricht 

 as from 2000 to 5500 ft.), being only about 1000 ft. It was, how- 

 ever, growing in company with one or two other alpine species, 

 viz. Cynodontium virens and Hypnum hamulosum. 



P. Mullerianum has been recorded from a considerable number 

 of localities in the Alps, and also from the Pyrenees, Caucasus, 



* I have taken the synonymy from Limpricht {Lauhmoose). 



