482 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



glacialis is one of the three mosses gathered in Cockburn 

 Island, lat. 64° 57' south ; the others being Tortula kevipila 

 and Tortula gracilis, so that species of this tribe seem to 

 have greater powers of endurance than any others. 



7. RiPARiACEi, Br. (t Sc, Mont. 



Aquatic ; sporangium immersed in the leaves, or more or 

 less exserted ; lid conico-rostrate, spiral ; peristome consisting 

 of thirty-two teeth, connected together by anastomosing pro- 

 cesses, or of an ii'regular fissured, sometimes rudimentary, 

 membrane ; top of the columella dilated and connected with 

 the peristome ; leaves dark green. 



531. The three species of which Cinclidotus is composed, 

 and which is the sole European tenant of this tribe, differ 

 from each other in the acrocarpous and cladocarpous growth 

 of the fruit. They agree more or less with Fontinalis in 

 habit, and are allied to Tortula, from which they differ prin- 

 cipally in the anastomosing processes which connect the lower 

 portion of the teeth. These are not always definite in number. 

 The teeth, in fact, are quite rudimentary in C. aquaticus. 

 Like most aquatic plants, they are capable at times of growing 

 in the free air ; and the terrestrial variety, C. riparius, which 

 is at present the only one which has been found in England, 

 is quite a Tortula in habit. Wardia and Scouleria, which 

 are also aquatic, seem near allies. In Scouleria, which grows 

 in streams amongst the Rocky mountains, there is a process at 

 the top of the columella with which the thirty-two laciniated 

 teeth are probably at first in connection. In Wardia, which 

 is found at the Cape, there is the same dilated columella, the 

 peristome consisting of an irregularly fissured membrane. 

 There can be little doubt that these plants are intimately 

 united ; and if so, the character of the tribe will depend not 

 on the cancellation, but on the dilated columella. No species 

 appears in the Antarctic or New Zealand Floras, though 

 Wardia may be expected in the latter. 



8. Hydropogonei, 3Iont. 



Aquatic ; sporangium equal, concealed amongst the leaves ; 

 peristome none or simple ; operculum plane or acuminate ; 

 leaves nerveless. 



