COTYLEDONS. 



605 



its apex, and is connected with the cells of the reserve-tissue at that point. In 

 germination the cotyledon increases in length and pushes the hypocotyl with the 

 embrj^onic bud and radicle out of the seed. The food absorbed from the reserve- 

 tissue by the remaining portion of the cotyledon is conducted from the interior 

 of the seed to the extruded embryo by the lengthened part of the cotyledon. With 



Fig. 143.— Mangroves near Goa on the West Coast of India at ebb-tide. 



the help of food thus conveyed to it, the embryo is enabled to develop its radicle 

 into an absorbent root penetrating into the ground, and also to develop its leaf- 

 rudiments into green leaves. Numerous modifications of the process here only 

 sketched quite generally may be distinguished, and these consist chiefly in the 

 varying direction and length of the portions of the cotyledon thrust out from 

 the seed. In sedges, rushes, and cyperuses germinating in marshy ground, or even 



