ANALYTICAL CLASS-BOOK OF BOTANY. 



pericarp, with the seeds irregularly immersed in its sub- 

 stance, as the Grape, Gooseberry, and the Currant, fig. 

 1 0. The fruits of the Egg-plant, Potato, Orange, and 

 Lemon, are berries, the two latter being distinguished by 

 a thick and spongy rind. 



478. THE PEPO is an indehiscent pulpy fruit, closely 

 allied to the berry. It is formed of three united carpels 

 covered by a firm rind, and usually exhibits a fleshy 

 structure between the epicarp and the pulp that invests 

 the seed. The Gourd, Melon, and Pumpkin, are well 

 known illustrations. In many cases, the dissepiments 

 are obliterated in growth, so that the pericarp becomes 

 one-celled, and the placenta) parietal; but in the early 

 stages, the three carpels, with all their parts, may be dis- 

 tinctly traced, as they are seen in the Prickly Cucum- 

 ber, fig. 18. The fruit of the Papaw resembles the 

 pepo. 



479. THE POME is an indehiscent fleshy pericarp, 

 formed of two or more horny or bony carpels, which are 

 invested with the swollen and succulent tube of the trans- 

 formed calyx, as in the Pear, Quince, and the Apple, 

 figs. 1 and 6. The five carpels are well shown in the 

 transverse section, and the structure of each, with its 

 position in the pome, in the vertical section. In the 

 Apple, the outer skin is the epicarp, the fleshy portion 

 the sarcocarp, and the bony carpels which invest the seed, 

 or that part which, in common language, we term the 

 hull, is the endocarp. 



480. THE DRUPE is an indehiscent, one-celled, and 

 one or two-seeded fruit, with the endocarp hard or stony, 

 investing one or two seeds, and the epicarp pulpy or 

 fleshy, as in the Walnut, Cherry, and Peach, the two last 

 of which are seen in figs. 15 and 21. The epicarp, in all 

 these cases, is greatly expanded, and the fruit takes an 

 increased development by cultivation. The Walnut, 

 which was considered by the old Botanists as a nut, is 

 now ranked among drupaceous fruits. The outside shell, 

 or thickened husk, is a fleshy epicarp, the shell is the 

 endocarp, and the kernel the seed. 



481. THE ACHENIUM is a dry, indehiscent, one-seeded 

 pericarp, formed of a single carpel, which is so closely 

 applied to the seed, that it was long mistaken for the seed 

 itself, from which it is often difficult to distinguish it 

 without a close analysis. By cutting across the fruit, 

 the true seed may be seen lying free in the pericarp. 

 Hence Linnaeus fell into the error of calling such fruits 

 as were composed of achenia, naked seeded ; but they 



The Achenium and Caryopsis? Fruit of the Papaw. What have the 

 Achenia been called ? Why change the term ? Why real fruits how in the 

 Crow-foot tribe in the Strawberry the Mint tribe the Composites the 



are all furnished with a style, which determines their 

 true origin and nature. They are, in short, mature 

 ovaries, and therefore fruits. 



482. The achenia are variously disposed in different 

 fruits. In the Crow-foot tribe, they are collected on a 

 dry, convex receptacle. At fig. 19 is an achenium from 

 one of this family, greatly magnified. In the Fennel 

 tribe, there are always two achenia united by their faces, 

 so as to form a compound fruit, with a division between 

 them, called the COMMISSURE, which makes an important 

 feature in the analysis of that large and difficult family. 

 In the Mint tribe, the four achenia, which lie loose in 

 the bottom of the calyx, have a common style, to which 

 each of them is attached by the base. In the Strawberry, 

 the achenia are arranged on a convex receptacle, and 

 when ripe, they are immersed in pulp ; while in the 

 Blackberry and Kaspberry they form little drupes. 



483. What have usually been considered seeds, in 

 the large family of Composite, are, in fact, single-seeded 

 fruits invested with the tube of the calyx, the limb of 

 which assumes a variety of shapes, called pappus, as you 

 have already learned (386). In the Clematis, the styles 

 are remarkably prolonged and plumose, and they are also 

 conspicuous in some of the Sedges. A vertical section 

 of the fruit from one of this family is shown at fig. 16. 

 The dark-colored albumen, or nucleus of the seed, is seen, 

 with its integument, which is separable from the invest- 

 ing pericarp, and its minute embryo at the base. This 

 structure clearly demonstrates the true nature of the 

 achenium, especially by the addition of the long styles 

 which show that it has a real pistil, and therefore is a true 

 fruit. At fig. 20 is an achenium of the Fumitory. The 

 Strawberry, Blackberry, and Kaspberry, are not, strictly 

 speaking, simple, but aggregate fruits. 



484. THE CARYOPSIS is a dry, thin, and membranaceous 

 pericarp, investing the seed so closely, as to be insepara- 

 ble from it ; and in the last respect it differs from the 

 achenium. The grains of Wheat, Rye, Maize, and most 

 Grasses, furnish examples. At fig. 1 1 you will see a fruit 

 of this kind in the Oat grain. All such fruits have been 

 considered seeds, but by examining them in the early 

 state, and especially by the attachment of the styles, we 

 find that they are really composed of the expanded ovary, 

 and therefore fruits. 



485. A NUT is a hard, dry, indehiscent pericarp, 

 usually composed of two or more carpels, with one or 

 more ovules in each, but reduced to one by suppression, 

 as in the Beech and Oak. The Nut is often inclosed by 



Raspberry the Fennel tribe? Name the division between the compound 

 fruit in the lost. What, properly speaking, are the Strawberry and like I'ruiU? 



