Fruit. When seeds are formed, contiguous parts become more or less modified, and the resulting structure is called a fruit. The parts involved in a fruit vary widely in different plants. Sometimes only the ovary is involved, as in the bean-pod; sometimes the cup-like part of the flower which bears the floral leaves is included, as in the apple; sometimes the very much enlarged receptacle is included, as in the strawberry; while in the pineapple the fruit is the whole flower-cluster, with its axis, bracts, flowers and all. Fruits may be roughly classified in two groups: (1) those which ripen dry and (2) those which ripen fleshy. The dry fruits are further divided into those which dehisce, that is, open in some way to discharge the seeds, and those which do not dehisce, the fruit being carried away with the seed. Among dry fruits which do not dehisce are the akene (sometimes spelled achene), in which a single seed is so closely invested by the ovary as to make a seed-like fruit, as in the sunflower, dandelion, strawberry pits etc.; and the characteristic grain of wheat, corn and other cereals. Among dry fruits which dehisce, called in general pods, are the follicle, a single ripened carpel which splits down one side, as in the peony; the legume (generally called pod), a single ripened carpel which splits into two parts (valves), as in the pea and bean; the capsule, a ripened pistil of several carpels which opens in various ways, as in the hollyhock and violet; the silique, the peculiar pod of the mustard family, with a false partition; the silicle, a short silique; the pyxis, a capsule which opens by a lid, as in the twin-leaf (Jeffersonia). The fleshy fruits do not dehisce, and among them are the berry which is pulpy throughout and with a thin rind, as the grape, currant, tomato etc.; the drupe or stone fruit, in which the ovary wall develops an outer fleshy part and an inner bony part (stone), the seed being the kernel, as the peach, cherry, plum etc.; the drupelet, a small drupe, as the grains of the blackberry, raspberry etc.; the pome, in which certain flower-parts outside the ovary; form the flesh, as the apple, pear etc., the ripened ovary being the core.
VARIOUS FORMS OF DRY, DEHISCENT FRUIT