INTRODUCTION TO CRYPTOGAMIC BOTANY. 487 



are punctate. In OodonoblepharuTn tlie peristome is double, 

 and the inner consists of sixteen cilia arising from a basilar 

 membrane, and whose connivent tips form a sort of bell, from 

 whence the name. The species are in the first place inha- 

 bitants of Europe and North America; Zygodon conoideus 

 appears in Tasmania ; while Z. viridissimus is found in the 

 Neelgherries. The New Zealand species are southern species, 

 with the exception of Z. obtusifoUus, an Indian form ; while 

 Z. intermedius is found in Chili. 

 16. Tetraphidei, Br. & Sc, Mont. 



Sporangium erect ; calyptra mitriform, plicate ; peristome 

 united with the top of the columella, which is divided into 

 four pyramidal teeth ; teeth irregularly reticulated. 



640. The few species of which this small tribe is composed 

 are scarcely exceeded in interest by any mosses, for the peri- 

 stome, instead of consisting of a regular series of cells as in 

 other species, is merely a sort of membrane stretched over the 

 top of that portion of the columella which separates from that 

 which remains within the operculum, and with it splits into 

 four irregular teeth. It does not, indeed, seem quite certain 

 whether the four teeth are perfectly homologous with the 

 teeth of other mosses ; authorities differ in this respect. At 

 any rate, the arrangement of the cells is not symmetrical. 

 Tetraphis pellucida forms dense green patches at the roots of 

 trees or on peaty banks, while Tetrodontium Browrdcmwm is 

 remarkable for its dark colour, and the absence of anything in 

 addition to the perichsetial leaves, except long strap-shaped 

 processes, which seem as much entitled to the name of branches 

 as of leaves. Tetraphis pellucida occurs in N. America, but 

 I am not aware that any species of the tribe is found in the 

 southern hemisphere. 



17. BtrxBAUMiEi, Br. & Sc, Mont. 



Sporangium slipper-shaped, oblique, pedunculate, or sessile; 

 calyptra short, conical. 



541. This small but highly curious tribe consists of two 

 genera only. The first, Buxbaumia, has a large apophysate 

 sporangium, flat above and convex below, seated obliquely on 

 a rough stalk with a small calyptra, just covering the Hd : the 



