HANDBOOK OF BRITISH HEPATIC^. 63 



Porella thuja, Dicks. 



Csespitose, stem ascending, subpinnately 

 branched, above convex, smooth, leaves closely 

 imbricated, lower lobe spreading, elongated, 

 recurved, entire; interior ovate, rather obtuse, 

 margin reflexed; stipules oblong, acute, entire, 

 margin reflexed, recurved at the apex ; peri- 

 chaetial lateral, emergent, leaves larger, ciliately 

 serrate. 



Jungermannia thuja, Dicks. Crypt. 4, p. 19; 

 Taylor Trans. Bot. Soc. Edin. II., 116. 

 Madotheca thuja, Dumort. Comm., p. in. 

 Porella thuja, Carr. and Pears. Exs. No. 46. 

 Jungermannia platyphylla v. thuja, Hook. 

 Jung. t. 40, fig. 



On stones by lake sides. 



Tufts wide, olive green, the older parts purplish 

 brown, shining, the shoots acuminated. In plants 

 with perichaetia the branches are very short. It may 

 be known from P. platyphylla by its greater size, its 

 shining surface, its acuminate shoots, its denser 

 structure, its perichaetia prominent beyond the stem 

 leaves, its perichaetial leaves larger, wider, more di- 

 vergent, and always ciliately-serrate, its divisions less 

 regularly pinnate, the closer imbrication of the 

 leaves, and the more patent position of their 

 inferior lobes. Taylor. (Plate 2, fig. 20.) 



Porella pinnata, Lind. 

 Stems irregularly pinnate, or subdichoto- 



