84 



cn yp TOGA MO us r ypes. 



tlieir ends projecting above it. The nucule is a row of 

 cells of which the highest is the germ-cell, and the whole 

 answers, in fact, to the archegonium of the Bryophytes 

 and Pteridophj'tes. It is in this plant called the cai'j^Ofjo- 

 niiim. Just below it is a globular body made up of eii;ht 

 triangular shield-shaped segments arranged about a cen- 

 tral cavitj\ From the inner end of each segment several 

 coiled filaments, of many cells each, pro ject into the cavity. 

 At maturity the shields separate, and the filaments even- 

 ttially break up into their constituent cells, each of which 

 tlien liberates an antherozoid. The antherozoids make 

 their way down the necks of the carpogonia and fertilize 

 the germ-cells. The spiral cells then harden, and form a 

 firm coat for the spore within. As the plant decays in 

 the autumn, these seed-like sporocarps, as they are now 

 called, drop off and full to the bottom of the water, where 

 thej'' eventually germinate. On germination, they first 

 produce a simple form to which the name pro-embryo has 

 been given, and from which arises the plant-body which 

 bears the antheridia and carpogonia. 

 Tliere is, therefore, displaj^ed in this case an alternation of 



generations. • 

 Chara belongs to a group of plants known as AlgSB. They 

 grow either in the water or upon damp svirfaces. They 

 differ from the Fungi principally in developing chloro- 

 phyll, so that they are able to assimilate. In colour, the 

 Algae are often green, but in other cases the chlorophyll 

 is obscured by the presence of other colours, such as 

 brown and red. In the lowest forms of both Algse and 

 Fungi reproduction takes place by simple division of the 

 cells. In higher forms the entire contents of two similar 

 adjacent cells coalesce to form a new one, from which the 

 new plant springs. This is the process of conjugation. 

 In still higher forms, as in Chara, reproduction takes 

 place by fertilization. 

 The Algse, Fungi, and Lichens together constitute a great 

 group called Thallophytes. 



Fig. 317 



Fig. 318. 



Fig. 319. 



