212 TORTULACE^E. 



This species and the next are nearly allied, but W. curvirostris can be distinguished 

 in the field by the leaves usually (but not constantly) more narrowly and longly 

 acuminate, and by the capsules darker, firmer and more solid, on longer seta?, the 

 mouth usually wider than the rest of the capsule ; also by the longer, firmer, dark 

 lid. Under the microscope the two are at once separated by the small, short, opaque 

 cells of the present plant, and the almost (or quite) plane margins of the leaves ; in 

 the next species the cells are larger, often longer, almost empty, and clearly defined ; 

 and one margin at least is recurved. 



The taller, more luxuriant forms of W. rupestris are more frequently barren, and 

 might be confused with Zygodon Mougeotii. 



13. Weisia curvirostris CM. (Pottia curvirostris Ehrh. • 



Barbula curvirostris Lindb., Braithw. Br. M. Fl. ; Gymnostomum 



curvirostre Hedw., Schp. Syn., et plur auct.) (Tab. XXXI. F.). 



Resembling the last in habit, but more frequently of a paler 

 green, a little softer and less rigid, fragile, 1-4 inches high. 

 Leaves erect and hardly twisted when dry, rather more narrowly 

 tapering and acuminate , one or both margins recurved below, nerve 

 less strong; cells at base pellucid, elongate-rectangular, above 

 rectangular, elliptical and sub-quadrate, larger, pellucid and 

 distinct, incrassate, more or less papillose. Seta 2-4 lines long; 

 capsule ovate or rounded-ovate, rarely oblong ; thick-walled, 

 glossy, dark reddish brown, after the fall of the lid wide-mouthed 

 and somewhat truncate ; lid longly and obliquely subulate, 

 attached to the columella and often persistent for some time ; 

 peristome none. Spores larger, 18-22 /*. 



Var. fi. commutata (Hymenostylium commutatum Mitt.). 

 Tall, brownish ; leaves long, narrow, more rigid, the cells all 

 elongated, smooth. 



Var. y. scabra {Barbula curvirostris forma scabra Lindb.). 

 Leaves short, papillose, cells quadrate ; stem and back of nerve 

 highly papillose. 



Hab. Mountain rocks in damp situations ; frequent. The vars. more rare m r 

 var. scabra, Ben Lui. Fr. late summer and autumn. 



The var. commutata has some claim to take a higher rank than a mere variety, 

 the areolation in its typical, or extreme form, being very distinct. Intermediate 

 forms however occur ; indeed, a fairly connected chain of forms exists from the above 

 variety with its very smooth tissue and elongated, pellucid cells, through the forma 

 laviuscula Lindb., which may be looked upon as the type, with smooth stem, 

 moderately papillose leaves, and shorter, but somewhat variable areolation, to the 

 var. scabra, with the whole stem rough with papilla;, extending up the back of the 

 nerve, and the areolation short, quadrate, and papillose. The Ben Lui plant 

 mentioned above as belonging to this variety, which I gathered in 1893, is remark- 

 able in also having the empty capsules very narrow-obloDg, slightly curved, with a. 

 rather narrow, oblique mouth. 



The points of difference between this and the last species are described above. 

 Aiuzctangium compactum differs from both in the bright green soft tufts, with rather 

 larger leaves more broadly pointed. 



