27 



CHAPTER IV. 



PROPAGATION OP MOSSES INDEPENDENT OP THE 

 FRUCTIFICATION. 



In all plants, besides the normal mode of fructification, there 

 are subsidiary modes of multiplying individuals, in contra- 

 distinction to species, and these are peculiarly abundant in 

 Cryptogams. "Without some provision of this kind, many 

 dioecious Mosses, in which the plants of the two sexes rarely 

 if ever occur in the same tuft, would of necessity die out. 

 Provision has however been made in various ways to supply 

 the defect, or to be accessory to the more normal rule. 



The true rootlets, together with those which are produced 

 so abundantly on the stem, or occasionally on other parts, are 

 themselves not unfrequently a means of multiplication. With- 

 out adverting particularly to those cases in which they develope 

 plants of a different sex from the parent, the lower roots espe- 

 cially as in some Phasca and Polytricha, send up to the sur- 

 face green threads, which can scarcely be distinguished from 

 those which are due to the germination of the spores, and 

 which, like them, generate buds, which in due time give rise 

 to perfect plants. Conferva velutina (Bng. Bot. t. 1556) is a 

 well-known example. 



Threads are also produced from the surface of the leaves, 



