J. E. Klett
Fruit ‑ A matured ovary along with any adnate structures.
Seed ‑ A matured ovule.
I. Simple fruits ‑ a simple fruit consists of a single ripened ovary (developed from a single pistil), plus, in some species, such adherent parts as sepals, stamens, etc. Fruits of most angiosperms are simple fruits. The major types of fruits are:
A. Fleshy fruits ‑ most or all of the pericarp is soft and fleshy at maturity.
1. Berry ‑ A one to many‑seeded fruit. The entire pericarp becomes fleshy, e.g. grape, banana, tomato, holly, honeysuckle, pomegranate. A berry with a hard rind is called a pepo, e.g. watermelon, cucumber.
2. A berry with a leathery rind is called a hesperidium, e. g. citrus.
3. Drupe ‑ Exocarp is a thin skin, the mesocarp is thick and fleshy, and the endocarp hard and stony. The endocarp (stone or pit) encloses one, rarely two or three seeds, e.g. peach, plum, olive, cherry, apricot, Symphoriocarpos, walnuts, coconut, almond.
B. Dry fruits ‑ The entire pericarp becomes dry and often brittle or hard at maturity.
1. Dehiscent fruits ‑ split open along definite seams at maturity. Contain several to many seeds.
a. Legume (pod) ‑ A one carple fruit which dehisces along both ventral and dorsal sutures, e.g. pea, bean, locust, caragana, peanut, catalpa.
b. Follicle ‑ consists of one carpel which splits open along one seam, e.g. larkspur, peony, spirea, magnolia.
c. Capsule ‑ consists of two or more fused carpels and splits open in various ways, e.g. lily, tulip, horse chestnut.
d. Silique ‑ consists of fused carpels which separate at maturity leaving a persistent partition between e.g. mustard, cabbage.
2. Indehiscent fruits ‑ do not split open along definite seams at maturity. Usually contain only one or two seeds.
a. Achene ‑ Bearing one seed, which is inseparable from the ovary wall, except at point of attachment of seed to inside of pericarp, e.g. sunflower, dandelion, sweet shrub.
b. Samara ‑ A one or two‑seeded fruit, the pericarp of which bears a flattened wing‑like outgrowth, e.g. elm, maple, ash.
c. Caryopsis (grain) bearing one seed, the coat of which is completely fused to the inner surface of the pericarp, e.g. corn, wheat, oats, rye, rice and other grasses.
d. Schizocarp ‑ composed of usually two fused carpels which split apart at maturity, each part containing usually a single seed, e.g. carrot, dill, parsnip, celery.
e. Nut ‑ a one‑seeded fruit, much like an achene, but with a much thickened, very hard pericarp, e.g. acorn (oak), hazelnut, chestnut.
II. Aggregate fruits ‑ A cluster of several to many ripened ovaries (or pistils) produced by a single flower and borne on the same receptacle. The individual ripened ovaries may be drupes (as in raspberries and blackberries), achenes as in buttercups, etc.
III. Multiple (compound) fruits ‑ a cluster of several to many ripened ovaries produced by several flowers crowded on the same inflorescence. As in aggregate fruits, the fruitlets of a compound fruit may be drupes, berries, nutlets, etc. e.g. mulberry, fig, pineapple.
Accessory fruits ‑ fruits in which parts other than ovaries adhere to or enclose the mature ovules, e.g. strawberry, in which the individual fruits are achenes, borne upon a sweet, fleshy receptable (the edible portion).
Another common accessory fruit is the pome, e.g. apples, pears and quince, in which the ovaries are surrounded by enlarged receptable and floral tube tissues in which large amounts of food and water are stored. Thus, in strawberry and pome fruits the edible portions are not the matured ovaries, but stem and floral tube tissues, in which the ovaries or true fruits are imbedded.