204 



BOTANY. 



consist of an ovoid carpogone ahd a globular antherid, 

 which are barely visible to the naked eye. 



375. The carpogone (Fig. 120, s) is a single cell, as in 

 Coleochaate (p. 168), which soon becomes covered by the 

 growth ol a layer ol cells from below. This covering, 

 which here develops before fertilization, is homologous with 

 the protective covering which in ColeochEete, Red Sea- 

 weeds, Powdery Mildews, etc., forms after fertilization has 

 taken place. 



376. The antherids (Fig. 130, a) are globular many- 

 celled bodies, in the interior of which certain cells produce 

 antherozoids. Each antherozoid is a long spiral thread of 

 protoplasm, provided with two long cilia at one end, by 

 means of which they swim rapidly through the water. 



Fig. 119.— a Stonewort (Chara crinita). One half the natural size. 

 (From Allen.) 



377. Fertilization takes place by the antherozoids swim- 

 ming down the opening at the summit of the covering cells 

 (Fig. 120, c). The carpogone and its covering now be- 

 . come thicker-walled and constitute the proper spore-fruit. 

 The latter soon drops off and falls to the bottom of the 

 water, where it remains at rest for a time. 



