52 APLOPERISTOMI. \_Tortula. 



Fontinalis alpina. Dicks. Crypt. Fasc. 2,t.^.f. 1. 



Racomitrium fontinaloides. Brid. Meth. p. 80 Dill. Muse. t. 33. 



/2. 



HAB. Growing on stones and wood, in streams of water. 

 Plant from four to six inches long, brandies of a dark lurid 

 green colour. Leaves imbricating the stem on every side, 

 elliptico-lanceolate, acuminated, margined, entire, flexuose, 

 curled when dry, nerve strong. Perichsetial leaves nearly as 

 long as the fruit, much acuminated. Fruitstalks shorter than 

 the capsule. Capsules oblong, smooth, brown ; lid conico-acu- 

 minate. Peristome bright red, rigid, arising from the reticu- 

 lated membrane; teeth numerous, capillary, slightly twisted, 

 below anastomosing. 



XIII. TORTULA. 



GEN. CHAR. Fruitstalk terminal ; Peristome single, of 3 

 spirally twisted teeth, united more or less at the base 

 into a tubular membrane ; Calyptra dimidiate. (TAB. II.) 



Not only in the Syntrichice of Bridel and Mohr, but in several 

 other species of the present genus, is the membrane which unites 

 the teeth at the base sufficiently visible ; as, for example, in T. 

 muralis, T. tortuosa, and T. unguiculata, likewise in the exotic T. 

 serrulata, and T. Australasia ; so that we cannot avoid reuniting 

 the SyntrichicB with the older genus Tortula. 



We follow, in the arrangement of the species, that which Dr. 

 Hooker and Dr. Greville have adopted in their Memoir on the 

 genus Tortula, published in the First Volume of Brewster's Jour- 

 nal of Science, p. 287. 



A. Leaves rigid, nerveless. 



1. T. enervis ; stem very short, leaves few Ungulate very obtuse 

 concave nerveless rigid, the margins involute, lid conico-acu- 

 minate rather shorter than the oblong capsule. (SUPPL. 

 TAB. II.) 



