186 ELEMENTS OF BOTANY. 
they never open, are usually taken by those who are not 
botanists for seeds. 
In the group of plants to which the daisy, the sunflower 
and the dandelion belong, the akenes consist of the ovary and 
the adherent calyx-tube. The limb of the 
calyx is borne on the summit of many 
akenes, sometimes in the form of teeth, 
sometimes as a tuft of hairs or bristles, 
Fig. 174. 
220. The Grain. — Grains, such as 
corn, wheat, oats, barley, rice and so on 
have the interior of the ovary completely 
filled by the seed, and the seed-coats and 
the wall of the ovary are firmly united, as 
Fig. 170.— Chestnut, a 
Single Fruit. 
shown in Fig. 9. 
221. The Nut.— A nut, Fig. 170, is larger than an akene, 
usually has a harder shell and commonly contains a seed 
which springs from a single ovule of 
one cell of a compound ovary, which 
develops at the expense of all the 
other ovules. The chestnut-bur is a 
kind of involucre, and so is the acorn- 
cup. The name nut is often incor- 
rectly apphed in popular language, 
for example, the so-called Brazil-nut 
is really a large seed with a very 
hard testa. 
222, Indehiscent and Dehiscent Fie. 171.—Group of Follicles 
Fruits. — All of the fruits so far  n¢ & Sings Rolie ae 
considered in the present chapter are 
indehiscent, that is, they remain closed after ripening. Dehis- 
cent fruits when ripe open in order to discharge their seeds. The 
three classes which immediately follow belong to this division. 
223. The Follicle. —One-celled, simple pistils, like those 
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