148 ELEMENTS OF STRUCTURAL BOTANY. 



example. In "Wheat the fruit differs from that of Buttercup 

 in having a closely fitting and adherent pericarp. Such a 

 fruit is called a carijopsis or grain. A nut is 

 usually syncarpous, with a hard, dry pericarp. 

 A winged fruit, such as that of the Maple (Fig. 

 208), is called a samara or key. 



242. A fruit which splits up when rii)e into 

 several one-seeded pieces is called a schizocarjj. 

 The samara of the Maple is a good example ; j^^ 

 also the fruit of Catnip, which splits up ^^ 

 at maturity into four one-seeded portions. \/ 

 Fig. 206. The fruit of Mallow is another common ^'^•^"'■ 

 instance. The separate portions in these cases are called 

 mericarps. In some leguminous plants 

 the pod breaks up transversely inio one- 

 seeded portions, giving rise 

 J. aj» to the form called a lament. 

 \ Iwk ^^^' "^ special schizocarp 

 is that of Umbelliferous 

 plants (Fig. 209). Here the Fi^. m 



fruit splits into two mericarps, each attached, 

 however, by a fibre to the axis. • Such a fruit 

 is called a creinoearp. 

 244. The Seed. The seed has already been described 

 as the fertilized ovule. During the formation of the 

 carpels, the ovules arise as outgrowths from the inner 

 surface of the ovary, mostly, as has been pointed out, 

 upon the margins of the carpellary leaves, but occasion- 

 ally also upon the surface generally. At first the ovule 



Fig. 206.— Silicle of Stock. Fig. 207.— Pyxis of Purslane. 



Fig. 208.— Samara of Maple. 



Fig. 209.— Cremocarp of an Umbellifor ; a, the fibre attacliing the uiericarp 

 to the axis. (Thorut^.) 



