BEPKODUCTIVE ORGANS OF PLANTS. 331 



comes off is the seed-vessel together with the outer coat- 

 ings of the seed. Barley-grain, in addition to the seed- 

 vessel, has the petals of the flower or inner chaff, and 

 oats have, besides these, the calyx or outer chaff adher- 

 ing to the seed. 



Pod is the name properly applied to any dry seed-ves- 

 sel which opens and scatters its seeds when ripe. Sev- 

 eral kinds have received special designations ; of these 

 we need only notice one. 



The Legume is a pod, like that of the bean, which 

 splits into two halves, along whose inner edges seeds are 

 borne. The pulse family, or papilionaceous plants, are 

 also termed leguminous, from the form of their fruit. 



THE SEED, or ripened ovule, is borne on a stalk which 

 connects it with the seed-vessel. Through this stalk it 

 is supplied with nutriment while growing. When ma- 

 tured and detached, a scar commonly indicates the point 

 of former connection. 



The seed has usually two distinct coats or integuments. 

 The outer one is often hard, and is generally smooth. 

 In the case of cotton-seed it is covered with the valuable 

 cotton fiber. The second coat is commonly thin and 

 delicate. 



The Kernel lies within the integuments. In many 

 cases it consists exclusively of the embryo, or rudimen- 

 tary plant. In others it contains, besides the embryo, 

 what has received the name of endosperm. 



The Endosperm forms the chief bulk of all the 

 grains. If we cut a seed of maize in two lengthwise, we 

 observe, extending from the point where it was attached 

 to the cob, the soft " chit," b, Fig. 63, which is the em- 

 bryo, to be presently noticed. The remainder of the 

 kernel, a, is endosperm ; the latter, therefore, yields in 

 great part the flour or meal which is so important a part 

 of the food of man and animals. 



The endosperm is intended for the support of the 



