n6 



NATURE ( »F THE SEED 



pyle, exists in the integument. This opening is seen near the 

 scar or hilum that marks the point where the seed was attached 

 by a minute Stem to the walls of the ovary i Fig. 83, B). This 



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V. t 





Fig. 83. Fruit and seed of the bean: ./. mature fruit or pod: s, style; 

 <-. remains of calyx; 0, ovary. At left the pod has been opened, showing 

 four -cols attached to the walls of the ovary by funiculus. B, two views 

 of a seed — h, hilum <>r scar marking attachment <>f funiculus to seed; m, 

 micropyle. C, wrinkling of seed coat caused by the entrance of water 

 through the micropyle and hilum. D, embryo of seed after removal of 

 integument — c, cotyledons. At left one <>f the cotyledons has been removed 

 to show the plumule, "r epicotyl, ep, and the hypocotyl, fry. E, half of the 

 membranous integument. 



opening permits the- entrance of the air and water as does the 

 r structure of the hilum. Tin's can easily be demonstrated 



by placing beans in water when the spread of the water from the 



u of the soicropyle will he indicated by the swelling and 

 wrinkling of tin- integument (Fig. 83, C). After a time the 

 entire integument becomes quite soft and water is readil) drawn 

 through it owing to the fact that the storage foods in the embryo 



are in close COntad with it and draw the water through 1> 



mosis. Carefully removing the integument from a soaked bean 

 we note that the embryo is will developed, consisting of two 

 fleshy cotyledons ami a short stem (Fig. 83, /'. / 1. The epi- 

 cotyl is well developed forming a plumule bearing two leaves 



and the short hypOCOtyl and rout are enclosed in a sheath formed 



from the integument. Note that the hypocotyl and root are 

 situated near tin- micropyle. Ilow- does this arrangement work 



