THE SEED 



61 







(fig. 21 c ; 5) . The part of the embryo lying close to 

 the endosperm is called the scutellum (fig. 21 b, d ; sc.= 

 scutellum). It is a kind of modified leaf and represents 

 the cotyledon of the embryo. In this case we find only 

 one cotyledon instead of two. 



The nature as well as the position of the endosperm 

 may differ in different seeds. In grasses, for instance, 

 it is mealy ; it is such endosperm which forms the 

 essential part of flour, 

 the embryo being com- 

 paratively small. The 

 embryo lies to one side, 

 and comes into contact 

 with the endosperm 

 only by means of its 

 scutellum. In the poppy, 

 on the other hand, the 

 embryo is surrounded by 

 the endosperm, and em- 

 bedded in it ; and the 

 endosperm is not mealy, 

 but is fatty and oily (see 

 fig. 21 a ; Z>=endosperm, SC. 

 em.=embryo). Lastly, in 

 coffee beans the greater 

 part of the seed consists 

 of hard, horny endos- 

 perm, and the very small 

 embryo is on one side 

 enveloped by the endo- 

 sperm. A curious experiment will reveal the presence 

 of the embryo. Coffee beans are known to have already 

 lost their germinating power when they reach us ; in fact 

 they possess that capacity only for a few days after being 

 gathered ; but if soaked in boiling water, or, still better, 

 in a solution of caustic alkali, we notice what appears to 

 be the germination of a seed which is certainly dead. 



FIG. 21. 



