44 SEEDS AND SEEDLINGS. 



76. Seeds with Food stored in the Young Plant. In 



the following notes we shall take first seeds which resemble 

 the Broad Bean in having nothing within the seed-coat 

 except the young plant, which therefore contains the food- 

 store, usually in the cotyledons the Brazil " nut " is excep- 

 tional in having the food stored in the hypocotyl. 



It will be noticed that in some cases the term " akene " is 

 used for what are usually called seeds. This means that the 

 apparent seed is in reality a one- seeded fruit, corresponding 

 to a Bean pod in which only one seed has developed and the 

 shell or fruit-wall does not split open to let the seed out 

 this is true of most, though not all, one-seeded fruits. Note 

 also that in akenes (often spelt achenes) the actual seed-coat 

 is thin, since the shell or fruit-wall amply protects the young 

 plant and there is no need for a stout seed-coat ; also that it 

 is, of course, useless to look on the outside of an akene for 

 the micropyle and the scar of the seed- stalk, since the seed 

 itself lies within the shell and is attached to the inner surface 

 of the latter by the seed- stalk. 



You can easily tell an akene from a seed, especially if you 

 get the whole collection of akenes produced by the plant, e.g. 

 the "cob" of Maize or the fruiting head of the Sunflower, 

 for a seed is developed inside a fruit, while an akene, being 

 itself a fruit, is carried on the outside of the plant and 

 usually shows some traces of the style and stigma. 



77. French Bean (Phaseolus vulgaris) and Scarlet 

 Runner (P. multiflorus) . In both, note the position of 

 the scar ; the micropyle, made very conspicuous by its raised 

 margin ; the beautiful wrinkling of the coat when the seed is 

 soaking; the two large first foliage-leaves of the young 

 shoot, plainly showing the veins. Sketch the seeds and 

 the seedlings, comparing them with those of the Broad Bean 

 (Fig. 22). 



Sow the seeds and note that in the Eunner the cotyledons 

 remain below, as in Broad Bean, while in French Bean they 

 are pushed up into the air along with the plumule, because 

 in the latter plant the hypocotyl that portion of the young 

 plant's axis which lies between the root and the insertion of 

 the cotyledons grows in length, carrying up cotyledons 



