THE SEED 



Whole Seed 



r Section 



Peel off the brown coat, which is the covering or 

 TESTA of the seed. The yellow structure thus ex- 

 posed is the EMBRYO or the baby plant. On gently 

 pressing the embryo, it, separates into two thick fleshy 

 halves ; these are the seed-leaves or cotyledons (c, c) 

 of the embryo. On the face of one of the two coty- 

 ledons is seen a minute, yellow structure near the 

 pointed end; this is the axis of the embryo, repre- 

 senting the axis of the future plant. The pointed end 

 of this axis near the pointed end of the cotyledons is 

 the RADICLE (r) or future 

 root, and the opposite end 

 of the axis is the plumule 

 (p) or future stem. The 

 two cotyledons are hinged 

 at the axis between the 

 radicle and the plumule. 



The radicle, plumule, 

 and cotyledons together 

 form the embryo of the 

 seed. Thus chhola or 



Gram is a seed consisting of an embryo covered with 

 a testa (i). 



But all seeds are not of this nature. Some contain 

 within the testa an oily or mealy substance, called 

 endosperm or albumen, in addition to the embryo. 

 Take, for example, a rerhi (fig. 7) or Castor seed; 

 it consists of a thin, linear, central embryo embedded 

 in abundant oily endosperm, which is covered over 

 with a dark-coloured horny testa. 

 : Seeds like chhola are therefore said to be ex- 

 albuminous or without endosperm, whereas seeds 

 like rferhi are said to be albuminous or with en- 

 dosperm.. Examine the following seeds and make 

 out whether they are albuminous, or exalbuminous: 



Fig. 7. — Rerhi or Castor-oil Seed 

 (Jitcinus camtnutiis) 



a. Aril. c. Cotyledon. ^, Plumule. 

 r. Radicle, i, Testa. 



