WEEDS OF THE FARM AND GARDEN 



when the ovule is curved on itself, as in chickweed; am- 

 phitropous, when the body of the ovule stands trans- 

 versely to the stalk; anatropous, when the ovule is in- 

 verted and the opening close to the hilum; the ridge 

 extending along the ovule is called the raphe. 



The fruit is the matured pistil, including whatever 

 parts are attached to it. The seed vessel is called the 

 pericarp. The principal kinds of fruit are: The simple 

 fruit, resulting from the ripening of a single pistil, an ex- 

 ample being the bean pod; the 

 simple fruits are divided into 

 the dry fruits, stone fruits and 

 berries; an aggregate fruit 

 formed when a cluster of car- 

 pels of a single flower are crowd- 

 ed in a mass, as in the rasp- 

 berry; and multiple fruit formed 

 by the union of a cluster of 



pistils of several flowers, as in 

 Fig. Sl> Two cotyledons r 

 of bean; r, radicle; p, plum- the mulberry, 

 ule. An exalbuminous seed Fruits may also be divided 



into dehiscent and indehiscent. 



The dehiscent fruits are repre- 

 sented by the legume, a true pod which comes from a simple 

 pistil with dehiscence on both sides, as in the pea and bean ;the 

 follicle, a pod formed from a simple pistil and dehiscent by the 

 ventral suture, as in the larkspur ; capsule, a dehiscent fruit 

 of a compound pistil. Modifications are a pyxis, which 

 opens by a circular line, as in the purslane and plantain ; 

 silique, like the pod of the mustard, which has two parietal 

 placentae. The indehiscent fruits are nearly always one- 

 seeded, the more important kinds being the achene (ache- 

 nium), a one-seeded, seedlike fruit, like that of the sun- 

 flower, buttercup and smartweed ; samara, a keylike fruit 

 provided with a wing, as in the maple and ash ; the utri- 

 cle, somewhat like an achene, but with a loose membrane, 



