MUSCI AND HEPATICAE 



463 



species may be seen in the near neighbourhood. But occasionally tlic 

 method of spread is more precise. Thus the spores of some Mosses 

 are sticky, and readily carried by insects. This is so with the dung- 

 infecting Splachnum, the agent of its spread being the dung-fly. 

 Scattered in one way or another, the spore germinates in presence 

 of moisture, giving rise to filaments, which as they grow are partitioned 

 into cells, and soon branch. Some of the branches are exposed at the 

 surface of the soil, and develop chlorophyll. Others penetrating 

 the soil are colourless, or have brownish walls ; they serve as rhizoids 



Fig. 357. 

 a, b, c, germination of Moss-spores to form protonema <* = formation ^ol j bud 

 laterally upon the protonema. e = diagrammatic plan of the segmentations of d, as 

 seen from above. (After H. Muller.) 



(Figs. 356, 357). The filamentous system thus produced is called pro- 

 tonema, and the formation of Moss-Plants is regularly preluded by this 

 filamentous stage. If grown in dim light the protonema may increase 

 indefinitely, but with full exposure it sooner or later forms Moss-plants. 

 These arise as buds, each taking the place of a branch of the protonema, 

 and may be held to be a condensed form of it. The segmentation 

 of the bud is from an initial cell, by walls with rather more than 

 120 degrees of divergence, as shown in ground plan (Fig. 357, 4 e )- 

 Each segment gives rise to a leaf of the Moss-Plant, borne on the 

 upward-growing stem. Bud-formation does not check the growth of 

 the protonema, which may still extend indefinitely. Branches from 

 the rhizoids may anywhere rise above ground, sooner or later 



B.B. 



2G 



