THE FEUIT. 



83 



467. Dehiscence. — Some fruits always remain 

 closed, as the Acorn, Cocoa-nut, and Apple. Such are 

 said to be Indehiscent, or not opening. The Dehiscence 

 of fruits is quite an important feature of discrimination 

 in all true analysis, and therefore should be defined. 

 It is 



(1) Septicidal, when the fruit opens by the ventral 

 suture, and the carpels separate between their contiguous 

 walls, as in the Gentian, fig. 22. 



(2) LocuLiciDAL, when it opens by the dorsal suture 

 directly into the cell, as in the Iris, fig. 14, the Lily, fig. 

 8, and the Meadow Saffron, fig. 11; 



(3) Septifragal, when the valves break off from the 

 dissepiments, as in the Morning-Glory and the Thorn- 

 Apple, fig. 10 ; 



(4) Sdtueal, when a single carpelled fruit opens by 

 the ventral suture, as in the Peony; by the dorsal suture, 

 as in the Magnolia ; or by both the ventral and dorsal 

 sutures, as in the Bean and the Pea, fig. 18 ; and 



(5) Transverse, when it describes a line directly 

 across the sutures, and the upper part opens and falls 

 back like a lid, as in the Plantain, Purslane, Henbane, 

 and the Scarlet Pimpernel, fig. 9. This form is of rare oc- 

 currence. The Loment, fig. 23, separates in a transverse 

 direction between every two seeds. 



468. To these may be added several varieties. In 

 the familiar instance of the Poppy, the fruit opens by 

 pores at the summit, as in fig. 13. In the Balsamine, fig. 

 12, the pods, when ripe, are very irritable; and on being 

 touched or jarred, the valves fly open elastically, and 

 scatter the seeds ; and hence its common name. Touch- 

 me-not. In some of the Tobacco and Primrose families, 

 the pericarp opens only for a short distance ; and in the 

 fruit of the Castor-oil plant, the dehiscence is first loculi- 

 cidal, and then the carpels separate from each other in a 

 septicidal manner^ In Mustard, and others of the Cru- 

 ciferaj, the parietal placentae are united by a membranous 

 partition, from which the valves separate in dehiscence, 

 from the base upward, as in figs. 16 and 19. The Straw- 

 berry, Currant, and Peach, figs. 17, 20, and 21, are inde- 

 hiscent fruits. 



FRUIT FORMS. 



469. The forms of the pericarp are exceedingly varied ; 

 but the most important and strongly marked are the fol- 

 lowing : the Capsule, the Silique, the Silicle, the Le- 

 gume, the Follicle, the Berry, the Pepo, the Pome, the 

 Drupe, the Nut, the Caryopsis, the Aehenium, the Sa- 



TarietiM of Dehiscence. Define each, with examples. How in the Tobacco 

 and Primrose families — the Castor-oil plant — Mustard — Balsamino ? Principal 

 Frnlt Forms. Define esteh, with examples. Parts of the Capsule— define. 



mara, the Pyxis, and the Cone. All fruits are either- 

 simple or collective. 



SIMPLE FRUITS. 



470. These may be composed either of a single car- 

 pel, or of several united ; and they are not always de- 

 veloped from the pistil alone, but they also often com- 

 bine with this, other parts of the flower. 



471. A Capsule is a pericarp of a dry and woody 

 texture. It is always compound in structure, because it 

 is produced from a compound ovary, although in growth 

 it frequently becomes one-ceUed, as we have seen (461), 

 by the absorption or rupture of its walls. The fruits of 

 the Iris, Scarlet Pimpernel, Lily, and Thorn-apple, figs. 

 2, 7, 13 and 22, Plate XXVIL, are all Capsules. 



472. Parts of the Capsules. — These are, 



(1) The Valves, or parts into which it separates by 

 dehiscence, as in the Iris, fig. 2 ; and 



(2) The Columella, or central portion, formed by 

 the united placentae, when the placentation is axillary, as 

 in the Lily, fig. 13. 



473. The Siliqub is a long, slender, two-valved pod, 

 which becomes two-celled by a false dissepiment, though 

 produced from a simple ovary, as in fig. 3. The pods of 

 the Mustard and Cabbage are familiar examples. This 

 and the following form distinguish the Cress tribe, and 

 are always marked by the cruciform corolla. 



474. The Silicle differs from the silique only in 

 being broader and shorter, as in fig. 4. The Pepper- 

 grass and Candytuft are well-known examples. 



475. The Legume is a simple, one-celled pod, dehis- 

 cing by both the ventral and dorsal sutures, as in the Pea, 

 fig. 5 : ejp is the epicarp ; en the endocarp ; pi the 

 placenta, which is double, and runs along each edge of the 

 ventral suture; and /is the funiculus, or little stalk, 

 by which the ovules, o, are attached to the placentae. 

 The Legume distinguishes the Pea tribe, and is usually 

 accompanied by the papilionaceous corolla. The Lo- 

 ment, fig. 12, is a variety of legume, which separates 

 transversely into one-seeded joints, as in Bush Clover, 

 and various species of Trefoil. The legume, in Lucerne, 

 is coiled up in a spiral form ; and in a species of Cassia, 

 it is like a little cupboard with partitions or shelves, 

 where the seeds are deposited. 



476. The Follicle is a one-carpelled fruit, folded 

 in the form of a pod, and dehiscing by the ventral suture, 

 as in the Peony, MiLk-weed, and the Indian Hemp, 

 fig. 17. 



477. The Berry is a pulpy or fleshy indehiscent 



Difference between the Follicle and Legome— the Legume and Loment— the 

 Silique and Silicle ? 



