4io 



A TEXT-BOOK OF BOTANY. 



The wall of the fruit is called the pericarp, and, like the leaf, 

 it consists of three distinct layers, viz. : ( i ) the outer layer corre- 

 sponding to the outer epidermis of the ovary is called the epicarp 

 or EXOCARp; (2) the inner layer corresponding to the inner 

 epidermis of the ovary is called the endocarp, or, from the fact 

 that it is sometimes hard and stone-like, it is called the putamen, 

 as in the prune; and (3) the middle layer situated between the 

 epicarp and endocarp is called the mesocarp ; and from the fact 

 that it is sometimes succulent or fleshy, as in the prune, it is also 

 called the sarcocarp. 



There are a number of distinctive and descriptive names applied 

 to fruits. Some of the more imoortant are as follows : 



Fig. 237. A, transverse section of colocynth showing seeds (s) borne on parietal 

 placentas; B, transverse section of fruit of Ricinus communis showing septicidal dehis- 

 cence of capsule, the seeds (s) being borne on axial placentas; C, transverse section of card- 

 aniom showing loculicidal dehiscence, the seeds (s), as in B, being borne on axial placentas. 



An Achene is a non-fleshy, or so-called dry, unilocular and 

 one-seeded, indehiscent fruit, in which the pericarp is more or less 

 firm, and may or may not be united with the seed. Achenes may 

 be inferior, as in the Compositse (Fig. 227), where they develop 

 from inferior ovaries, being frequently surmounted by the pappus 

 or calyx; or half inferior, as in the rose (Fig. 236, G)y where they 

 develop from half inferior ovaries ; or superior, as in the buttercup 

 (Fig. 223,/)). 



A Berry is a fleshy, indehiscent fruit, the seeds of which 

 are embedded in the sarcocarp; berries are superior when they 

 develop free from the torus, as in belladonna (Fig. 239), capsi- 

 cum, grape, etc., and inferior when the torus forms a part of 

 the fruit, as in banana, cranberry (Fig. 244), and gooseberry 

 (Fig. 245). 



