300 FEUIT OR MATURE PISTIL. 



of the ovary, divisions may take place in the fruit which did not 

 exist in the ovary. In Pretrea zanzibarica a one-celled ovary is 

 changed into a four-celled fruit by the extension of the placenta. In 

 Cathartocarpus Fistula (fig. 429, p. 244) a one-celled ovary is 

 changed into a fruit having each of its seeds in a separate cell, in con- 

 sequence of spurious dissepiments being pro- 

 duced in a horizontal manner, from the inner 

 wall of the ovary after fertilisation. In Tri- 

 bulus terrestris, each cell of the ovary (fig. 

 534) has slight projections, c, on its walls, in- 

 terposed between the ovules, o, which, when 

 the fruit is ripe, are seen to have formed dis- 

 _. ,„. tinct transverse divisions (fig. 535 c), or 

 spurious dissepiments, separating the seeds, g. 

 In Astragalus, the folding of the dorsal suture inwards converts a one- 

 ceUed ovary into a two-celled fruit ; and in Oxytropis the folding of 

 the ventral suture gives rise to a similar change in the fruit. 



The development of cellular or pulpy matter frequently alters the 

 appearance of the fruit, and renders it difficult to discover its formation^ 

 In the Strawberry, the axis becomes succulent, and bears the carpels 

 on its convex surface ; in the Rose there is a fleshy hollow torus or 

 disk, which bears the carpels on its concave surface. In the Goose- 

 berry, Grape, Guava, Tomato, and Pomegranate, the seeds nestle in 

 pulp formed apparently by the placentas. In the Orange, the pulpy 

 matter surrounding the seeds is formed by succulent ceUs, which are 

 produced from the inner partitioned lining of the pericarp. 



The pistil, in its simplest state, consists of a carpel or folded leaf, 

 with ovules at its margin ; and the same thing will be found in the 

 fruit, where the pericarp, as in the Bean (fig. 536), represents the 

 carpellary leaf, and the seeds correspond to the ovules. The pericarp 

 consists usually of three layers ; the external (fig. 536 e), or epica/rp 

 It/, upon, or on the outside, xajTos, fruit), corresponding to the lower 

 epidermis of the leaf; the middle (fig. 536 m), or mesocarp (//.'eeo;, 

 middle), representing the parenchyma of the leaf; and the internal 

 (fig. 536 n), or endocarp (evdov, within), equivalent to the upper 

 epidermis of the leaf, or the epithelium of the ovary. In some plants, 

 as Bladder Senna (Colutea arborescens), the pericarp retains its leaf- 

 like appearance, but in most cases it becomes altered both in con- 

 sistence and in colour. Sometimes the three parts become blended 

 together, as in the Nut ; at other times, as in the Peach, they remain 

 separable. In the latter fruit, the epicarp is thickened by the addition 



Fig. 534, CeU or loculament of the ovary of Tribulus terrestris, cut verticaUy, to show 

 the commencement of the projections, c, from the paries, which are interposed between the 

 ovules, 0. Fig. 535. The same in a mature state, showing the transverse partitions, c, 

 dividing the fruit into cavities, in one of which a seed, g, is left. 



