298 A MANUAL OF MOSSES 



with hooked tips, prostrate to ascending or erect, with few or 

 no rhizoids, simple to regularly pinnate, rarely bushy ; branches 

 2-seriate, short and thick, or longer, acuminate and down- 

 wardly arcuate; leaves crowded, imbricate, falcate-secund, 

 concave, plicate, rugose. Scarcely decurrent, oval to oblong- 

 ovate, narrowed into a long, canaliculate, lance-subulate, sharp- 

 ly-toothed point, the margin more or less revolute; costa 

 simple, thin, sometimes reaching. to mid-leaf; median leaf-cells 

 narrowly vermicular, with dorsally (sometimes a few ventral- 

 ly, also) projecting and iorward-pointing teeth-like papillae at 

 the upper end of the cell, towards the costa at base the cells 

 more lax, rectangular, porose, incrassate, the alar region not 

 excavate, the alar cells forming a distinct longitudinal band 

 of small, quadrate and polygonal, yellowish,, incrassate, numer- 

 ous cells; ihner perichsetial leaves elongate-lanceolate, slender- 

 ly acuminate, plicate, serrate, ecostate : seta 2-5 cm. long, 

 castaneous, when dry twisted; capsule inclined to horizontal, 

 elliptic to sub-cylindric, dorsally gibbous, when dry arcuate 

 and constricted below the mouth, brownish ; annulus 3-seriate, 

 remaining attached to the operculum ; lid convex-conic, shortly 

 and obliquely rostrate; peristome normally hypnoid,; teeth 

 rusty-yellow, segments broadly split,, cilia 2, as long as the 

 segments ; spores in summer but capsules very rarely produced. 

 One species, as follows, on exposed sunny rocks and ledges, 

 and in dry, grassy places; Europe, Asia, and from Arctic 

 America through Canada to the northern United States. Usual- 

 ly in hilly or mountainous regions on calcareous stfbstrata. 

 Rare in our region. 



1. Rhytidium rugosum [Ehrhart] Kindberg. 

 (Hylocomiuni nigosum DeNotaris; Hypnum rugosum Ehrhart). 



Stems reaching 8 or 10 cm. or more, the branches tumid 

 and sometimes 4-6 mm. in diameter ; the leaves 3 mm. long or 

 more, sometimes costate above the middle, margins narrowly 

 reflexed. 



Huntingdon : T. C. Porter. (Porter's Catalogue). 



14. HYLOCOMIUM Bryologia Europasa. 



Dioicous, more or less robust, stiffly and laxly cespitose 

 in green or yellowish and more or less lustrous tufts : stem 

 mostly very long and procumbent or ascending, more or less 

 arcuate, once to three times pinnate; paraphyllia numerous, 

 much-branched; leaves more or less spreading, concave, most- 

 ly plicate, oblong to cordate, long-acuminate, plane-margined, 

 serrate; costa thiri, double, sornetimfes reaching mid-leaf; cells 

 linfcar, mostly smooth, basally shorter and laxer, colored, in- 

 crassate, porose, alar not differentiated ; inner perichaetia^ 



