COSCINODON. 157 



1. Ooscinodon cribrosus Spruce (Grimmia cribrosa Hedw.) 

 (Tab. XXIV. E.). 



In small, very dense cushions, sometimes confluent and 

 forming- wide patches, greyish green, hoary above, short. Leaves 

 crowded, spreading, appressed when dry, ovate-lanceolate or 

 shortly oblong-lanceolate, concave, margin incurved above ; 

 plicate or rather costate at back on each side of the nerve, 

 especially in the upper part ; nerve narrow, prominent at back ; 

 upper leaves ending in a long, almost smooth hair-point, which is 

 often wide at the base and extends down the upper part of the leaf 

 apex ; cells at base rectangular, rather pellucid, not sinuose, thin- 

 walled or slightly incrassate, more elongated near the nerve ; 

 above elliptical, then rounded, or quadrate, incrassate, smaller, 

 near apex often bi-stratose ; perichaetial bracts thinner, less 

 plicate. Seta short, straight, capsule immersed, erect, oval, 

 smooth, wide-mouthed when dry, lid conical, rostellate ; calyptra 

 covering most of capsule, lobed at base, thin ; peristome teeth 

 lanceolate , orange-red, much perforated. 



Hab. Siliceous rocks, very rare. Fr. summer, 



This little moss resembles Grimmia anodon and G. crinita in its dense, hoary 

 cushions ; but the capsule is different and the plicte of the leaves at once distinguish it. 

 These are rather dorsal bands of thickening cells with something the appearance of 

 secondary nerves than simple furrows ; they are in some leaves very indistinct. The 

 species differs too from the above plants in never choosing a calcareous matrix. 

 Grimmia conferta is also something like it, but the calyptra, the larger cells, longer, 

 narrower hair-point, and plicate leaves of the present plant will easily distinguish it 

 from that. 



32. PTYOHOMITRIUM B. & S. 



Plants in dense cushions ; leaves long, narrow, without 

 hyaline points, crisped when dry ; areolation not sinuose. Seta 

 straight. Capsule smooth. Calyptra campanulate , lobed, plicate. 

 Peristome teeth long, divided into two slender branches or almost 

 entire. 



1. Ptychomitrium polyphyllum Furnr. (Bryum polyphyllum 



Dicks. ; Glyphomitrium polyphyllum Mitt., Braithw. Br. M. Fl.) 



(Tab. XXIV. F.). 



In neat rounded dense cushions, y 2 -2 inches high, dark or 

 yellowish-green, blackish below. Leaves crowded, spreading and 

 flexuose when moist, strongly crisped when dry, large (2 lines 

 long), elongate-lanceolate from a broad, oblong, deeply plicate 



