ig6 TORTULACEiE. 



or elongated, the lowest cells all shortly rectangular and pellucid. 

 Capsule oval-oblong, smooth and shining ; lid rather short, less 

 acute than in B. fallax; peristome teeth from a short basal 

 membrane, short, free or united, oblique or slightly twisted. 

 Dioicous. 



Hab. Walls and rocks, frequent. Fr. late summer and autumn. 



When the fruit is present and in good condition, the short, hardly twisted 

 peristome, taken in conjunction with the rectangular basal cells, easily distinguishes B. 

 rigidula from its allies ; but this is rarely the case, and then it is extremely difficult to 

 separate from B. vinealis. That species is usually of a more decided green tint, the 

 leaves more acute in the acumen, and more flexuose when dry, with more strongly 

 papillose areolation, obscure with chlorophyll above ; stunted specimens however may 

 prove very difficult to determine. B. cylindrica is known by its longer, larger, curved 

 and flaccid leaves, B. fallax and B. sfadicea by the short, hardly altered basal areola- 

 tion, and the larger, more broadly pointed leaves ; B. gracilis and B. icmadophila 

 by the well defined cells and distinctly excurrent nerve. The time of fruiting in these 

 closely allied plants should be noted ; in B. fallax the capsules are ripened almost in 

 mid- winter, in B. rigidula, usually at least, in Jate summer and autumn, in B. vinealis 

 in spring. B. rigidula grows in small tufts, almost invariably on rocks or walls, while 

 B. fallax is frequently, indeed usually, terrestrial, and forms laxer, irregular patches. 



7. Barbula cylindrica Schp. (Zygotrichia cylindrica Tayl.) 

 (Tab. XXIX. H.). 



Plants rather soft, in loose tufts or patches, olive green 

 above, reddish brown below ; stems flexuose, slender, 1-2 inches 

 high. Lower leaves rather short and distant, the upper crowded 

 and longer, flexuose-curved , longly linear-lanceolate from a 

 rather long ovate erect base, widely spreading, much twisted and 

 curled when dry ; margin narrowly recurved, usually plane above 

 the middle ; nerve vanishing in the rather wide point ; areolation 

 small, irregularly hexagonal, very obscure, papillose, more 

 quadrate below, all the lowest shortly rectangular, small. Seta 

 long, flexuose ; capsule oblong-cylindric, dark chestnut brown, 

 smooth, shining ; lid acutely rostrate ; peristome spirally twisted, 

 short, not forming a complete turn, pale red. Dioicous. 



Hab. Walls, banks of streams, etc. , principally in calcareous districts ; 

 frequent. Fr. rare, spring and summer. 



Resembling B. fallax much in appearance, this species may generally be 

 distinguished by its greener tufts and softer texture, the leaves also are longer and 

 narrower in the limb, frequently horizontally flexuose in their direction. Under the 

 microscope the obscure, much smaller and usually more angular upper cells, and the 

 basal cells, all more or less quadrate or rectangular, easily distinguish it. The leaves 

 too are less recurved, and the margin less strongly revolute. The basal cells are 

 sometimes considerably elongated, and pellucid. 



