328 PHASCEI. PART n. 



von Mohl observes that since the cells in the dif- 

 ferent parts of mosses are capable of being developed 

 into a bud or embryonic confervoid structure producing 

 a bud, it follows that in these plants, notwithstanding 

 their rather complex structure, the subordination of the 

 individual cell to the purposes of the whole plant is 

 still but small ; and even here individual life readily 

 acquires the preponderance. This facility of reproduc- 

 tion possessed by the various individual parts of the 

 plants, accounts for the extensive tracts over which 

 mosses spread themselves ; moreover, some are dioecious, 

 and as the spores might not always be fertilized, the 

 gemmse ensure the continued existence of the species. 



Mosses are divided into five principal groups, differing 

 exceedingly in importance, and in comparative numbers. 

 They are chiefly distinguished by the position of their 

 fruit. The Pleurocarpi have their fruit lateral, whether 

 on the stem or branches. They comprise thirteen tribes; 

 many of them are found in the southern hemisphere, 

 but a considerable number, especially of the Hypnei, 

 Drepanophyllei, and Hookeriei, are European. The 

 Cladocarpi are characterised by having their urns 

 seated on the tops of very short lateral branches, and 

 by their double axis of growth. The Acrocarpi are dis- 

 tinguished by their main stems ending in fruit. They 

 comprise twenty-seven tribes, and embrace genera and 

 species having a wide geographical range. In the 

 Syncladei the branches of the plant are fasciculate ; this 

 group comprises the Sphagnuins. The Schistocarpi are 

 remarkable for their fruit splitting into valves, and 

 consist of the tribe Andrseacese. The various tribes 

 depend on the structure of the urns and leaves, as well 

 as on the natural habits of the plants. In this numerous 

 class of plants only a few remarkable for peculiarity of 

 structure can be mentioned. 



The species of the acrocarpous tribe Phascei are ex- 



