310 



PART IV. CLASSIFICATION. 



The sexual organs are borne on the adult shoot, and are an- 

 theridia and archegonia. They are rarely borne singly or scat- 

 tered, but more commonly in groups (sori) surrounded by some 

 kind of protective investment to which the general term involucre 

 may be applied. In some cases the portion of the shoot which 

 immediately bears the sexual organs is more or less specialised as 

 a receptacle, and in others special reproductive branches, gameto- 

 phores, are differentiated, and may be either antheridiophores or 

 archegoniophores. In the lower Hepaticse the sexual organs are 

 generally borne on the upper (dorsal) surface of the shoot, whilst 

 in the higher Hepaticse (Jungermanniacese acrogynse) and in the 

 Mosses they are borne at the apex. 



PIG. 191. Funaria hygrometrica (Moss). A Germinating spores : u rhizoid; s exospore. 

 H Part of a protonema, about three weeks after the germination of the spore : 7i a pro- 

 cumbent primary shoot with brown wall and oblique septa, out of which arise the 

 ascending branches with limited growth : K rudiment of a leaf-bearing axis with rhizoid 

 (tc). (A x 550 : B about 93.) 



The distribution of the sexual organs is various : the male and 

 female organs may be borne on distinct shoots, when they are 

 dio3Cious ; or on different branches of the same shoot, when they 

 are moncc.cious but diclinous ; or together in the same sorus, when 

 they are monoclinous. In Mosses it appears to be the rule, in 

 dicecious forms, that a protonema always bears both male and 

 female shoots. 



The sexual organs are always multicellular. The antheridium 

 (Figs. 192, 193) is a capsule of various shape, having a longer or 



