REPRODUCTION 



199 



the cndosixM'iii aiul to Iransinit it to the j>;rowinji; portions of the 

 embryo. 



The ripe seed is thus a structure in which the partially developed 

 young plant, well protected and provided with an abundant 

 supply of food for future growth, is able to pass through a more or 

 less extended period of dormancy. 



A B C D E 



Fig. 112. — Th estructure of a seed. A and B, side and face views of a bean 



seed. C and D, side and face views of the embryo after the seed-coats have been 



removed. E, the two cotyledons spread apart, revealing the plumule within. 



Af , Micropyle. //, Hilum. Co^., Cotyledons. T/^/p., Hypocotyl. P/., Plumule. 



The Fruit. — The ripened ovary, together with its contents the 

 seeds, and with any other structures intimately associated with 

 these, is known as the fruit. The ripened wall of the ovary is 



Fig. 113. — ^A kernel (grain or fruit) of corn. .1, face view, showing outline of 

 embryo in the middle. B, longitudinal section. 1, Pericarp and seed coat, fused. 

 2, Endosperm. 3, Plumule. 4, Scutellum or cotyledon. 5, Radicle. 3, 4 and 

 .5 constitute the eml)ryo. 



called the pericarp. Fruits are various and many different types 

 are recognized and named, but we shall mention here only the 

 most common and important of them. Some are dry at ma- 

 turity and split open. Such are the capsule (as in the lily), 

 which arises from a compound ovary, and the pod (as in the 



