4. The follicle, which splits on one side only, through the placenta.
5. All other fruits that split are termed capsules. Some of these split longitudinally, some transversely, and others by forming pores for the escape of the seeds.
The chief kinds of indehiscent fruits are:—
1. The drupe or stone-fruit, which consists of a hard stone surrounded by a fleshy covering, as the plum and the cherry.
2. The berry, which is soft and fleshy, and contains several seeds, like the currant and the grape.
3. The nut or achene—a fruit with hard and dry walls, as the filbert and the acorn.
4. The samara or winged fruit, like that of the sycamore.
Various modifications of these indehiscent fruits are to be met with; thus, the blackberry is not really a berry, but a cluster of little drupes formed from a single pistil of many carpels. A berry, too, may be made up of many parts, as is the case with the orange. The apple and similar fruits consist of a core (the true fruit) surrounded by a fleshy mass that is produced from the receptacle of the flower; and the strawberry is a succulent, enlarged receptacle of the flower, with a number of little achenes (the true fruits) on its surface.
The seed, as we have already observed, is the embryo plant. It consists of one or more seed-leaves or cotyledons, a radicle or young root, and a plumule or young bud. In many cases the skin of the seed encloses nothing more than the three parts of the embryo, as named above; but it sometimes contains, in addition, a quantity of nutrient matter in the form of albumen, starch, oil, gum, or other substance.