286 BARTRAMIACE^E. 



smooth, glossy j at first reddish brown, finally purplish black, hard, 

 horizontally cernuous ; calyptra narrow, cucullate ; lid conical. 

 Dioicous. 



Hab. Damp places on mountains, or among sand on shores ; rare. Fr. late 

 summer. 



This remarkable moss might easily, in the absence of fruit, be taken for one of 

 the Dicranaceae ; in habit it is not unlike Ceratodon, and the regular, rectangular cells 

 are much like those of Dicranella. The fruit however resembles that of no other 

 British moss except Discelium nudum ; and in spite of the above resemblances, the 

 leaves unite a number of characters not to be found in any single British species of 

 Dicranaceae, so that if attention be paid to the description there need not be any real 

 difficulty in identifying it. 



68. OONOSTOMUM Swartz. 



Densely csespitose, stems fastigiately branched. Leaves 

 imbricated in 5 rows, small; areolation as in Bartramia. 

 Capsule rounded, cernuous, striate. Peristome simple ; teeth 16, 

 long, narrow, united at apex so as to form a cone over the mouth 

 of the capsule. 



A small genus distinguished from Bartramia by the arrange- 

 ment of the leaves and the conical formation of the peristome. 



1. Oonostomum boreale Swartz. (Tab. XL. B.). 



Very compactly tufted, tomentose below, bright glaucous 

 green ; stems slender, fragile, fastigiately branched, £-2 inches 

 high. Leaves small, less than 1 line long, densely imbricated in 

 five rows, giving a pentagonal outline to the stems, when dry 

 closely appressed and sometimes slightly twisted in a spiral 

 direction ; lower widely ovate-lanceolate, upper gradually 

 narrower and longer, not plicate, keeled ; nerve stout, vanishing 

 in the lower leaves, in the upper excurrent in a short rigid brown 

 cuspidate point ; margin plane or very narrowly recurved in the 

 middle of the leaf, minutely denticulate with the projecting 

 transverse cell-walls ; cells rectangular with rounded angles, or 

 elliptic-rhomboid above, at base rather more lax, rectangular; 

 the marginal rather narrower than the median ; the upper faintly 

 papillose. Seta £-1 inch high ; capsule cernuous, variable in size, 

 ■widely oval, gibbous at back, deeply sulcate ; calyptra narrow, 

 cucullate ; lid rostellate ; peristome teeth inserted below the 

 orifice, deep red, linear-lanceolate. Dioicous. 



Hab. Peaty ground on the summits of the higher mountains; Scotland, 

 frequent ; Helvellyn. Fr. summer. 



