286 



PLANT LIFE. 



sjjerm. It is almost al\va)s ovoid or globular. The small 

 amount of bod)' protoplasm of the sperm may be looked upon 

 as merely accessory. That of the egg, however, is usually 

 abundant and well su])]ilied with reserve food, and it takes 

 part after fertilization in the formation of the new plant. 



388. The ovary. — The organ in which the egg is produced 

 is the ovary (oogonium, carpogcjnium, or archegoniiun). 

 Usually but one egg is ])roduced in each ovary, though as 

 many as eight are formed in the Fucacefe 

 (fig. 327). The ovary is either simple 

 or compound. 



389. A simple ovary consists of a 

 single cell, the bulk of whose proto- 

 plasm becomes one egg (or several). 



3^4- Fig. 325. 



Fig. 324. — Fgg of />/r;/,f as it lluats in se:\-\\ater, surrounded by many .sperms, one of 

 wliich e\'entua]ly plunges iutu it, unites with its nucleus and so fertilizes it. .Magnified 

 350 diani, — After Thuret. 



Fig, 32^, — Portion of two o\anes of an alga {S/>/i,t7-oy>h\i anunHna). Tlie upper part 

 contains two eggs, and a number (if sperms which have entered through the pore at 

 the side. The lower egg of the two shows the receptive spot above, A sperm is 

 partially imbedded in the protoplasm of tliis part in process of fertilization The 

 egg in the lower ovary has Ijeen fertilized and lias secreted a tliick wall, thus becom- 

 ing a resting spore, Ma,gnificd 500 diam, — After Cohn. 



A portion of the protoplasm of the ovary is almost inxarialily 

 excluded from the egg [B, fig. 30S). The sperms reach the 

 egg either through an opening formed in the wall of tlie 

 o\'ary (D, fig. 308, 325), or through a tube foriricd by the 

 spermary, which penetrates the oxary (fig. 307). 



