274 



THE CONTINUITY OF THE RACE 



and the style, stigma, and stamens wither away. The ovary, however, 

 enlarges with the growth of the ovule or ovules within it. Each ovule 

 becomes a seed, within which are contained an embryonic plant and a 

 supply of food stored in the endosperm tissues or in the seed leaves of the 

 embryo. The embryonic plant is a young sporophyte, with the diploid 

 number of chromosomes in all its cells. When the seed is mature, the 

 embryo has ceased to grow and has passed into a resting state, in which 



Fig. 17.19. Types of fruits. A to /, fleshy fruits; K to 0, dry fruits that split open when 

 ripe; W, X, aggregate fruits; Y, a multiple fruit. A, section through gooseberry (a typical 

 berry). B, chokecherry (drupe). C, poison ivy (drupe). D, ground cherry (berry enclosed in 

 papery calyx). E, cucumber (pepo), partly sectioned. F, orange (hesperidium), sectioned. 

 G, plum (drupe). H, H', walnut (drupe). /, hawthorn (pome). J, apple (pome). K, pea 

 (legume). L, larkspur (three follicles), M, lily (capsule), sectioned. N, lotus (capsule). 0, 

 mustard (silique). P, buckwheat (achene). Q, Q' , maize or corn (caryopsis). R, wafer ash 

 (samara). »S, maple (samara). T, ash (samara). U, bedstraw (schizocarp). V, V , acorn of 

 oak (nut). W, raspberry (aggregate fruit of small drupes). X, strawberry (aggregate fruit 

 of achenes on an enlarged receptacle) . Y, fig (multiple fruit, achenes on inner surface of an 

 enlarged hollow receptacle). (Modified from Turtox chart, courtesy General Biological Supply 

 House, Inc.) 



it can remain alive for a long time and await opportunity to resume its 

 development. Around it are the hard protective seed coats formed from 

 the ovule walls, protecting it from mechanical injury and too great water 

 loss. 



The matured ovary, enclosing its one or more seeds, together with any 

 other parts of the flower, such as the receptacle, that have shared in the 

 growth and maturation of the ovary, form the reproductive structure 

 known as & fruit. This is the botanical definition of a fruit, which includes 

 more than does popular usage. Thus botanically speaking, corn kernels, 



