THE LEGUMINOSvE 



31 



split across near the micropyle due to the expansion of the 

 embryo and a tiny rootlet makes its appearance, which at once 

 turns downwards following the law of gravity. Now lay some 

 of these germinating seeds in moist and loose earth and watch 

 their gradual growth. The plantlet first establishes itself in the 

 ground by growing a strong main root which sends off tiny 

 branches all round. Meanwhile the hypocotyl also grows upwards 

 forming a hook with its two cotyledons still folded over the 

 plumule. When the surface of the soil is reached, the hypocotyl 

 becomes straight, and now the two cotyledons unfold. Soon 

 after the first pair of opposite, cordate foliage leaves are deve- 

 loped and all the parts above the soil 

 grow green, the plantlet is now fully 

 developed and consists of root, stem and 

 leaves. As the stem continues growing 

 vigorously, one leaf after another, now 

 alternate and trifoliate, is developed 

 and the cotyledons be- 

 come thinner and final- 

 ly fall off withered. 



This process of 

 germination gives us 

 many things to learn. 



(a) If beans or any 

 other kind of seed are 

 laid on a dry spot, they 

 never germinate. They 



do so only when they are moistened. But then the question 

 arises: why does the mother-plant not furnish the seeds with the 

 water necessary for their germination at the very beginning, or 

 why are the seeds always so dry and hard when they are pro- 

 duced in the fruit of the mother-plant? If it were not so, the 

 seeds would try to grow as soon as they fall on the ground. But 

 the tiny weak roots could not make their way into the hard 

 ground, nor could they find any nourishment during the greater 

 part of the year. For, at the time when plants generally ripen 

 their seeds, the ground is dry and hard, the rains being over. 



Fig. 29. — Germination of Horse Gram. 



