312 



THE FRUIT. 



597. The Pcpo, or Goiird-frilU, is al>o a modification of tlie berry, 

 with a hard rind, whicli occurs in the Gourd family. Tlie cucum- 

 ber,, melon, and squash are familiar illustrations. A Pepo is an 

 indehiscent, externally firm and internally pulpy fruit, composed 

 usually of three carpels, and with an adnate calyx. In the ovary it 

 is either one-celled with three broad and revolute parietal placentne, 

 or these placenta}, borne on slender dissepiments, meet in the axis, 

 enlarge, and spread, unite with their fellows on each side, and are 

 reflected to the walls of the pericarp, next which they bear their 

 ovules (Fig. 560, 5G1). As the fruit enlarges, the seed-bearing 



placenta? usually cohere with the 

 walls, and the partitions are oblit- 

 erated, giving the appearance of 

 a peculiar abnormal placentation, 

 which only the study of the ovary 

 readily explains. 



598. A Pome, such as the apple, 

 pear, and quince (Fig. 809, 812), 

 is a fruit composed of two or more 

 carpels, either papery, cartilagi- 

 nous, or bony, usually more or less 

 involved in a pulpy expansion of 

 the receptacle or disk, and the 

 whole invested by the thickened and succulent tube of the calyx. 

 It may be readily understood by comparing a rose-hip with an apple. 

 The calyx makes the princi- 

 pal thickness of the flesh of 

 the apple, and the whole of 

 that of the quince. 



599. The Drupe, or Stone- 



Fruit, is a one-celled, one or 

 two seeded indehiscent fruit, 

 with the inner j^art of the peri- 

 carp (endocarp, or putamen, 

 588) hard or bony, while the outer (exocarp, or sorcocarp) is fleshy 

 or pulpy It is the latter which- in these fruits so readily takes 

 an increased development in cultivation. The name is strictly 



FIG. 5C0. Section of the ovary of the Gourd. 561. Diagram of one of its constituent carpels. ' 

 FIG 562. A'ertical section of a peach. 56.3 An almond ; where the exocarp, the portion 



of the pericarp that represents the pulp of the peach, remains thin and juiceless, and at 



length separates by dehiscence from the endocarp, or shell. 



