

of Smith, of the Order Musci. 223 



they must constitute so many distinct genera ; and in the sys- 

 tem these are placed very widely apart. 



The main characters, then, of the genus Hookeria, we con- 

 sider to depend, first, on the lateral insertion of the fruitstalk ; 

 secondly, on the peristome heing double, and like that of Hyp- 

 num and Leskea, having the inner one formed of a membrane 

 cut into sixteen segments, with or without intermediate ciliary 

 processes; and thirdly, upon its having a calyptra, which is 

 mitriform. 



There exists, at the same time, certain characters which are 

 common to a considerable portion of the species. The stems 

 in the greater number are creeping, and not unfrequently 

 clothed at the base with a reddish down ; in the arbusculoid 

 section they are erect. The leaves are sometimes exactly dis- 

 tichous, in almost every instance more or less hilarious, and 

 forming compressed or complanated branches ; their structure 

 is generally highly vascular, or in other words, loosely cellu- 

 lar and pellucid, on which account many are aptly compared 

 to Jungermannicc. The margin is occasionally thickened, 

 with or without serratures, the base sometimes oblique ; the 

 nerve rarely reaches to the point, is at times bipartite, but 

 more frequently double, the two being distant from each 

 other, sometimes wholly wanting. The fruilstalks are mostly 

 elongated ; but in H. concinna and pennata they are short ; 

 smooth, or scabrous, or even scaly, as in H. cristata. The 

 capsule, which often occurs reticulated,* is rarely erect, 

 sometimes inclined, but mostly drooping, and that in conse- 

 quence of the curvature of the upper extremity of the seta, 

 the capsule itself not being oblique or arcuate in the slightest 

 degree; this circumstance we esteem to be a remarkable fea- 

 ture in the capsule of this genus. The beak of the opercu- 

 lum, too, although often much elongated, is equally straight 

 in its direction. The form of the calyptra is almost as vari- 

 able as that of the genus Orthotrichum, being sometimes quite 

 entire at the margin, sometimes cleft into a few short and 



• We believe it will be found, that in those species of IJoolteria which have the 

 leaves most decidedly cellular, the capsule and calyptra are most strikingly reticu- 

 lated ; the rciculation being only caused by the enlargement of the cellules, as in 

 //. crutuia and lucens. In other species, we do not find the calyptra and capsule 

 to be reticulated ; hence wc do not consider that mark as being of suffici?nt conse- 

 quence to form a generic distinction. 



