Ch. XI] 



THE TRUE MOSSES 



489 



from a special ring, the annulus; beneath the operculum 

 is the peristome, which is a circle, sometimes two, of di- 

 versely marked slender teeth ; the spore case proper is a cham- 

 ber which surrounds a central columella, while outside of 

 the chamber occurs always some chlorenchyma. When the 

 spores are ripe, the operculum is forced 

 off by the swelling of the annulus, leav- 

 ing the capsule open except as guarded by 

 the peristome; and the movements of 

 the strongly hygroscopic teeth thereof 

 both permit and aid the ejection of 

 the spores. All these features of the 

 spore capsule, and especially of its peri- 

 stome, show remarkable diversity in 

 details of construction and ornamentation 

 in the different species (Fig. 347), pro- 

 viding indeed another instance of ap- 

 parent specialization far beyond bounds 

 of utility. The spores are disseminated 

 by wind, and on reaching a suitable 

 place, germinate into a branching, fila- 

 mentous, green protonema. On this ap- 

 pear buds, whence grow the vertical 

 stems, while new rhizoids enter the 

 ground from their bases. At the tips 

 of these stems, sometimes on the same 

 but often on different ones, appear 

 elongated archegonia and antheridia. In the antheridia 

 are produced many two-ciliate spiral free-swimming sperm 

 cells, which probably reach the vicinity of the archegonia 

 in splashing water drops. The opening archegonium puts 

 forth substances attractive to the sperm cells, of which the 

 first to enter the neck effects fertilization of the egg cell. 

 From this oospore develops the new sporogonium. 



As a whole the Mosses are rather uniform in habit. A 

 few species live in water (Fontinalis species), and are cor- 



Fig. 347. — Spore 

 capsule of the Moss, 

 Splachnum vasculo- 

 sum, illustrating ex- 

 treme structural 

 specialization ; X 65. 

 (From Kerner.) 



