48 BOTANY AND PHARMACOGNOSY. 



in height. At the tip of the branch the antheridium (Fig. 32, A) 

 and archegonium (Fig. 32, B) are formed. These organs are 

 developed in among the leaves and certain hairy processes, known 

 as paraphyses (Fig. 32, />) . They may both occur at the end of one 

 branch (Fig. 32, C) or they may occur on separate branches 

 (Fig. 32, D), when the plants are said to be monoecious, whereas 

 when these organs occur on separate plants (Fig. 32, A, B) the 

 plants are called dioecious. In the case of dioecious plants the 

 plant bearing the antheridium is frequently smaller and less com- 

 plex than the one producing the archegonium. As already stated 

 the archegonium produces the egg-cell or female gamete (egg) 

 and the antheridium, the sperm cell or male gamete (sperm). 



The sperms in the Bryophytes are more or less filiform and 

 are provided with a pair of cilia at one end. The antheridia 

 owing to the peculiar mucilagi-nous character of the cells only 

 open when there is an abundance of moisture, when the sperms 

 are discharged and move about in the water, some being carried 

 to the archegonium, which likewise opens only in the presence of 

 moisture. With the transferral of the sperms to the archegonium 

 and the union of one of these with the egg which remains sta- 

 tionary, the work of the gametophyte may be said to be com- 

 pleted. The act of union of the egg and sperm is known as 

 FERTILIZATION, and wlicu this is effected the next phase of the 

 life history begins. 



The egg after fertilization divides and re-divides within the 

 archegonium which becomes somewhat extended until finally it 

 is ruptured. The dividing cells differentiate into a stalk and a 

 spore case or sporangium which is borne at the summit, the whole 

 structure being known as the sporogonium (Fig. 28). The 

 base of the stalk is embedded in the apex of the moss plant, 

 and is known as the foot, it being in the nature of a 

 haustorium or nourishing organ. As the sporogonium de- 

 velops and rises upward it carries with it the ruptured 

 archegonium which forms a kind of covering over the top, 

 called the calyptra (Fig. 28. ca). At first the .sporangium is 

 more or less uniform but eventually differentiates into two kinds 

 of tissues, the one being sterile and the other fertile (producing 

 spores), which latter is known as the archesporium (Fig. 28, 



