208 



COMPENDIUM OF GENERAL BOTANY. 



In Fig. 128, (7, it is noticeable that the ring extends from r at 

 the left of the base of sporangium to r at the right. The cells of this 

 ring, when mature, are considerably thickened along the inner side, 

 as well as in the radial direction (vertical to the surface of the 

 figure). 



Fig. 129 shows the product of the fertilized archegonium. 

 The egg-cell has developed into a young plant with leaf, stem, and 

 root (5, s, w). The foot (f) of the embryo absorbs the food-mate- 

 rial (starch) of the spore at c ; i is the inner, ex the outer, spore- 

 membrane (exospore). The prothallium pt shows the root-hairs 



FIG. 129. Macrospore with prothallium FIG. 130. Longitudinal sec- 



and embryo of Marsilia salvatrix. tion through the tip of a 



(X 60.) (After Sachs.) fertile branch of Selaginella 



incequalifoUa. 



(After Sachs.) 



wh, and the mucous covering si which aids the spermatozoids in 

 reaching the egg-cell ; the root-hairs serve as a temporary attach- 

 ment to the soil at the bottom of the water. Fig. 130 shows a 



