THE FRUIT 
107 
all but one) of the loculi or the seeds, e.g. in oak, Betulaceae, 
&c. The calyx (or bracts) often persist and surround the 
fruit (cf. Physalis, Fagaceae, Corylaceae, &c.). 
Fruits may be divided first of all into simple, aggregate , 
and itiultiple. Where a flower gives one indivisible fruit, the 
fruit is simple, as in cherry or oak ; where it gives several 
similar fruits, independent of one another, as in raspberry, 
buttercup, Ochna, &c. the fruit is aggregate ; where several 
flowers combine to give one fruit, as in mulberry, fig, plane, 
the fruit is multiple (or collective ). In description, mention 
is made of the multiple or aggregate nature of the fruit 
and then one of the units is described as if it were a simple 
fruit. 
Fruits may be dry or fleshy ; they may open to allow the 
seeds to escape (i.e. may be dehiscent ) or may remain closed 
{indehiscent). Indehiscent dry fruits are usually one-seeded; 
it would be a disadvantage to have many seeds germinating 
near together. Fleshy fruits rarely dehisce ; they are eaten 
by animals and the seeds are thus separated. Some dry 
fruits, termed schizocarps , break up into one-seeded portions, 
or mericarps, usually corresponding to the individual 
carpels. 
Fruits usually only open in dry air, and remain closed, 
protecting the seeds, in moist air. Exceptions occur in 
xerophytes (Chap. III.), where protection is rather needed 
against drought. Colchicum and other autumnal plants 
protect their fruit during the winter by keeping it below the 
soil. In Arachis, Voandzeia, Trigonella sp., Amphicarpaea, 
Cardamine sp., &c., the (geocarpic) plant produces subter- 
ranean fruits, either from subterranean or subaerial flowers. 
In Erodium, Stipa, &c., the fruit has a self-burying me- 
chanism. Reference may also be made to Linaria, Cyclamen, 
&c. The fruit of Anthemis sp. has an outer mucilaginous 
layer, like that of many seeds. 
Classification , Descriptive Terms , 6rc. Dry indehiscent fruits are 
divided into two main groups, achenes and nuts. The achene is usually 
defined as the product of one carpel, the nut as that of more than one, 
but in practice all small seed-like one-seeded dry indehiscent fruits are 
achenes, all large ones nuts. True achenes are found in Ranunculus, 
Potentilla, &c. but the name is also given to the fruit of Compositae, 
