COTYLEDONS. 



607 



level of the seed (figs. 141 "^ and 141 ^^). Here loDg root-fibres develop from the 

 radicle and from the base of the hypocotyl; these burst through the cotyledon, 

 grow down into deeper layers of earth, and fix the J'oung plants in the spot 

 where the cotyledon has placed it. The apex of the cotyledon remains in the 



Fig. 144.— Germinating Seeds and Seedlings. 



' Seedling ol the Nasturtium (Tropaohim majus). - The same at an earlier stage of development, s Water Chestnut (Trapo 

 natans), from whicli the embryo is eniergiug. ■* Later stage of development. 5 Vouug seedling of the Austrian Oaii 

 (Quercits Austriaca). 6 The same, further developed " Seed of the Date (Phoenix dactr/li/era) from uhich tlie embryo is 

 emerging, s xhe same eight weelis later, after tlie seedling has already developed root and scale-leaves. 9 Young Date 

 in longitudinal section, lo Older Date in longitudinal section, ii .Seed of the Reed-mace Typha Shlttileworthii. 

 12 The same with protruding embryo, is The same at a later stage of development. 14, i^ .Seedling of the Sedge Carcx 

 vulgaris. Fig. 1-8, natural size; 9, 10, x 8; 11-13, x 4 ; 14, 15, x 6. 



seed, and here absorbs the last remnants of the i-eserve-materials. When these 

 are at last exhausted, one limb of the bent cotyledon grows upwards, and its 

 apex is di'awn out from the emptied seed-coat. All this occurs underground. 

 Now the cotyledon also has to reach the sunlight and become gi-een. This is 



