FRUITS 



which it separates at maturity. Gather a fruiting cluster 

 of fennel, parsley, caraway, etc., and examine one of the 

 small seedlike fruits through a lens. Separate the two 

 achenes of which it is composed, and find the carpophore 

 between them. Sometimes it splits in two (Fig. 145), one 

 half going with each achene ; or they may separate from 

 it through their entire length and remain suspended from 

 the top (Fig. 144). Notice the longitudinal ribs on the 

 back of the achenes, or mericarps, as they are called. 

 Between these ridges are situated the vittce, or oil tubes to 



which the aromatic 

 flavor of these fruits 

 is due. 



146, 147. Samaras : 146, ; 



147 

 lanthus ; 147, maple. 



90. The Samara, or 



key fruit, is an achene 

 provided with a wing 

 to aid in its disper- 

 sion by the wind. 

 The maple, ash, elm, etc., furnish familiar examples. 



91. The Grain, or caryopsis, so familiar to us in all kinds 



of grasses, is a modification of the 



achene in which the seed coats have 



so completely fused with the pericarp 



that they can no longer be distin- 



guished as separate organs. Peel 



the husk from a grain of corn that view. 



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 envel- 

 oped by its own coats. 



148, 149. Grain of broom 

 corn millet with husks on : 

 148, front view; 149, back 



Would it be any advan- 



r ,, , ,- 



ta S G f r the seed ot an 



indehiscent fruit, like a 

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



151 ** 



150-152. Gram of wheat: 150, back view ; 

 151, front view; 152, front view (magnified). 



