302 



FEUIT OE MATUEE PISTIL. 



points, and leaves a row of cavities in the substance of the pericarp 

 itself. 



In some fruits the calyx is superior, or in other words above the 

 pericarp, while in others it iS closely applied to the ovary, but 

 separable from it. Thus in the fruit of Mirabilis Jalapa (fig. 537, 1), 

 when a section is made longitudinally (fig. 537, 2), the hardened 

 calyx (perianth), c c, is distinct from the fruit, /, which is in this 

 instance incorporated with the seed, but at once distinguished by its 

 style, s. The same thing occurs in Spinach (Spinacia). Again, in 

 the Yew (fig. 538), there is an external succulent covering, ic, 

 formed by modified bracts, which here occupy the place of a pericarp, 

 and surround the seed, g, which is naked, inasmuch as it is not con- 

 tained in a true ovary with a stigma. 



1 



i 



Fig, 637, 1. 



Fig. 537, 2. 



The part of the pericarp attached to the peduncle is called its 

 base, and the part where the style or stigma existed is the apex. This 

 latter is not always the mathematical apex. In AlchemUla, Fragaria, 

 Labiates, and Boraginacese, it is at the base or side (figs. 434, 435, 

 436, pp. 246, 247). The style sometimes remains in a hardened form, 

 rendering the fruit apiculate ; at other times it falls ofij leaving only 

 traces of its existence. The presence of the style or stigma serves to 

 distinguish certain single-seeded pericarps fi-om seeds. 



As in the case of the carpel, so in the mature ovary formed of it, 

 the edges unite towards the axis, and constitute the ventral suture 

 (fig. 539 sv), while the back, corresponding with the midrib, is the 

 dorsal suture (fig. 539 sd). The inner suture in some fruits formed 

 of a single carpel, as the Apricot and Bladder Senna, is marked by a 

 distinct furrow or depression, consequent on the folding inwards of the 

 carpellary edges ; and occasionally the outer or dorsal suture is also 



Fig. 637. Fruit ot Mirabilis Jalapa. 1, Entire. 2, Cut longitudinally, to show its com- 

 position, c c. Lower part of perianth hardened, and forming an outer envelope. /, The true 

 fruit, covered by the perianth. The integuments of the fruit are incorporated "with those of 

 the seed, which has been also cut. The fruit is distinguished by the rema i ns of the style, s, 

 at the apiculus or summit. Fig. 638. Fruit of Taxus baccata, the Yew. h, Imbricated 

 bracts at its base, ic, Fleshy envelope taking the place of the pericarp. This envelope 

 covers the seed, g, partially, leaving its apex naked. 



