28 HANDBOOK OF BRITISH MOSSES. 



which propagate the plant, as in various Orthotricha. Con- 

 ferva muscicola (Eng. Bot. t. 1638) is a case in point. These 

 differ in degree of development. Sometimes they are green and 

 cylindrical or clavate ; sometimes they are scarcely distinguish- 

 able from rootlets. In Andre&a, the filaments assume a dif- 

 ferent type, and from the quadrifarious division of their en- 

 dochrome, so closely resemble some of the Palmelloid Algse, 

 that it is not easy to draw the line between them. 



In other cases propagating granules are produced on the 

 midrib, as in Pottia cavifolia (Plate 23, fig. 2 e), or articu- 

 lated clavate processes at the tip of the midrib, where it ter- 

 minates below the apex, as in the exotic Calymperes Afzelii 

 (Crypt. Bot. fig. 100 b], or at the very tip, as in Calymperes 

 rigida. Similar bodies to these last are produced on distinct 

 peduncles, as in Aulacomnion palustre and A. androgynwn 

 (Plate 18, fig. 5 g), where there are sometimes vertical as well 

 as transverse partitions, or in little rosettes, as in Tetraphis 

 pellucida (Plate 19, fig. 8 b, d). 



Sometimes, again, buds are produced in the axils of the 

 leaves, as in many Pleurocarpous Mosses. Even the leaves 

 themselves occasionally throw out rootlets below, and may 

 thus serve for propagation when broken off (Plate 8, fig. 5 b), 

 while those of Leucobryum glaucum often produce new plants 

 at their tips. 



The growth of Mosses from year to year by means of in- 

 novations, may also be referred to the same category, or at 

 least is closely analogous. But many annual, or at least ap- 

 parently annual, species are propagated on the same spot year 

 after year, not by innovations, but by radicular tubercles. 



