262 



PRACTICAL COURSE IN BOTANY 



.383 



384 



Figs. 382-384. — Cremocarps, fruits of 

 the parsley family. 



commonest of all fruits, and there are so many kinds that 

 special names have been applied to some of the most marked 



varieties. The akene of the 

 composite family may gen- 

 erally be known by the 

 various appendages in the 

 form of scales, hooks, hairs, 

 or chaff, that crown it (Figs. 

 309-314). The fruits of the 

 parsley family are merely a 

 sort of double akene at- 

 tached by the inner face 

 to a slender stalk from which it separates at maturity. 

 The samara, or key fruit, is an akene provided with a 

 wing to aid in its disper- 

 sion by the wind. The l^^ 

 maple, ash, and elm fur- 

 nish familiar examples. 



297. The grain, so fa- 

 miliar to us in all kinds of 

 grasses, is economically 

 the most important of all 

 fruits. It is popularly 

 classed as a seed, and for practical purposes may be treated 

 as such, but it is really a modification of the akene in which 

 the seed coats have so completely fused with the pericarp 

 that they can no longer be distinguished 

 as separate organs. Peel the husk from 

 a grain of corn that has been soaked for 

 twenty-four hours, and you will find the 

 contents exposed without any covering ; 

 remove the shell of an acorn or a hickory 

 nut, and the seed will still be enveloped 

 by its own coats. Would it be of any 

 advantage for the seed of an indehiscent fruit, like a grain of 

 corn or oats, to have a separate special covering of its own ? 



385 

 Figs. 385, 38G. 



386 



— Samaras : 385, ailanthus ; 

 38G, maple. 



387 



Figs. 387, 388. — Grain 

 of wheat with husks on : 

 387, front view ; 388, back 

 view. 



