THE PERICARP 105 



Kinds of Fruits. — From the foregoing considerations, we may deduce 

 the following definitions of fruits: 



A Fruit is a separate ripened carpel, or a separate part thereof, or an 

 aggre,c;ation of ripened carpels, together with any adherent j)arts. 



Multiple or Collective Fruits are those proceeding from the gynaecia 

 of more than one flower. 



Aggregate Fruits are those which proceed from a number of pistils 

 of one flower. 



Simple Fruits are those proceeding from a single pistil. 



Apocarpous Fruits are those consisting of one carpel or of two or 

 more non-coherent carpels. 



Syncarpous Fruits are those consisting of coherent carpels. 



Accessory Fruits are those in which some part other than the ripened 

 ovary constitutes a conspicuous portion. 



Structural Composition of the Typical Fruit. — The student cannot have 

 failed to note in reading the above statements that the composition of 

 the fruit is extremely variable and in some cases complicated. In 

 accordance with this fact, the classification of the parts of fruits is 

 o])en to great differences, according to the principles upon which the 

 observer bases his classification. The typical fruit may be considered 

 as that which consists only of the ripened pistil with the contained seed 

 or seeds. 



The Pericarp. — As a fruit is regarded as possessing but two portions, 

 namely, the seeds and the Pericarp, the pericarp of such a tyi)ical fruit 

 would consist of a ripened })istil exclusive of its seeds, but since, in many 

 cases, the calyx, disk, or other part is closely adnate to the wall of the 

 ovary and more or less indistinguishable from it, it becomes imprac- 

 ticable to restrict the term pericarp to a part consisting only of the 

 pistil. Again we find that there are all intermediate forms and degrees 

 of adnation and sei)aration between the ovary and the accrescent ])arts 

 of accessory fruits. It, therefore, appears most convenient to define 

 the pericarp in a broad sense as the fruit with the exception of the 

 seeds. 



The Pseudocarp or Anthocarp. — AVhen the pericarj) consists chiefly 

 of other elements than the ovarian wall it is called a Pseudocarp or 

 Anthocarp. 



Layers of the Pericarp. — When the pericarp is seen to consist of three 

 demonstrable layers, these are called respectively Fxocarp, the outer; 

 Endocarp, the inner; and Mesocarp, the middle. When the exocarp 

 is thin and membranous, like the skin of a plum, apple, or tomato, 



