12 THE SPHAGNACEsE OR PEAT-MOSSES OF 



CHAPTER III. 



THE VEGETATIVE SYSTEM. 



Germination of the Spore. 



To the investigations of Nageli and Hofmeister are we principally 

 indebted for our knowledge of the development of the plant, and 

 Professor Schimper further observed them under cultivation, and 

 found that on damp earth the spores germinated in two to three 

 months, and that the proembryonal cell rarely broke through the 

 exospore or outer coat in less than five weeks. 



The development proceeds under one of two forms, according 

 to the local conditions in which the spores may happen to be 

 placed at the time ; thus, if they be immersed in water, the ger- 

 minating proembryo assumes the form of a confervoid protonema, 

 somewhat akin to that of true mosses, but more elongated and 

 less branched ; from one end of this the young plant arises by a 

 tuberculoid aggregation of cells, while the other extremity becomes 

 a root, or one of the middle cells becomes the mother cell of the 

 new plant. But if the spore germinate on the damp ground, the 

 proembryonal cell goes on subdividing in a horizontal plane, and 

 the result is a lobed green prothallium like that of Equisetum, con- 

 sisting of a single layer of cells ; this hepaticine frond throws out 

 radicles from the under surface and margins of the lobes, and 

 quite resembles a plant of Blasia or Anthoceros. After a while, 

 cells aggregate here and there at the margins of the lobes and form 

 rudimentary plants, which support themselves partly from the 

 prothallium, partly by radicles ; in the plants growing in water 

 also, the radicles attach themselves to any fixed body, and thus 

 securely anchor the plants until they are in a condition to take care 

 of themselves. 



The roots in the young plants of Sphagnum precisely resemble 

 those of frondose mosses, consisting of slender elongated cells with 

 oblique transverse septa, and their functions are also similar, for 

 they serve both for support and nutrition ; as soon, however, as 

 the branches are produced, a portion of them become pendent and 



