184 President's Address. 



The reproduction of Mosses is effected in various ways ; 

 the principal being by the co-operation of the male 

 and female flowers ; the true function of which was first 

 established by Hedwig. Mosses are either monoecious, 

 dioecious, synoecious, or hermaphrodite ; the dioecious 

 species being in consequence rarely in fruit. The male 

 flowers are enclosed in a bud or dish-shaped perigone ; the 

 essential organs consist of an oval sac called the antheri- 

 dium. This is filled with a rather dense liquid, containing 

 an immense number of antherozoids, each consisting of a 

 thread-like body with biciliate spirals. These when free, 

 move rapidly in fluid, and thus penetrate the female organ 

 or archegonium. This body is contained in a circle or 

 cluster of leaves called the perigynium, and is flask-sliaped, 

 and like the antheridium is generally surrounded by jointed 

 threads. These are supposed to supply fluid to the sacs, thus 

 preventing them from being parched by great heat. 



During growth a central cavity is formed in the 

 archegon with a cell at the bottom, fixed only from below. 

 After impregnation this cell swells, and becomes the 

 young fruit, by enlarging into a conical form, and elongat- 

 ing into a stalk, and eventually tears through the middle 

 of the archegon, the upper part of which is carried up as 

 the calyptra, the lower portion remaining as a tube called 

 the vaginula, on which are often seen shrunk-up arche- 

 gonia. 



The fruit when perfect consists of a capsule with its 

 calyptra ; the centre of the capsule being generally occu- 

 pied by the columella, round which is the spore sac, in 

 which the spores are formed by septate division. 



The capsule usually dehisces by a lid called the oper- 

 culum, but in some species it bursts irregularly, wdiile in 

 the Andreseceee it splits into four valves, which, unlike the 

 Hepaticae, do not separate at the tips. At the base of the 

 lid is a ring of highly hygrometric cells called the annulus, 

 which probably assists in the throwing ofi" of the lid. 

 When the lid is removed, the spores are, in gymnostomous 

 Mosses exposed ; but in others they are more or less 

 covered by a thin membrane, or by one or two rows of 

 hygrometric teeth, called peristomes. These beautiful 

 organs have been supposed to be modifications of petals, 



