cucumber, (Cucumis sativus), creeping plant of the Cucurbitaceae family, probably originating in northern India and widely cultivated for its fruit. It is a tender annual with a rough, succulent, trailing stem and hairy leaves with three to five pointed lobes; the stem bears branched tendrils by which the plant can be trained to supports.
In northern Europe the cucumber is extensively grown in frames or on trellises in greenhouses; in the milder climate of the United States it is cultivated as a field crop and in home gardens. An excess of seed is sown, and the small plants are thinned to the number desired. The heat requirement is one of the highest among the common vegetables. There are three groups of varieties: the very large-fruited, strong-growing varieties adapted only to greenhouse or frame culture; the large-fruited, outdoor-grown plants generally having white spines, which are used primarily for slicing and pickling; and the small-fruited, prolific kinds with spines, including the gherkin, which are grown outdoors principally for pickling.
The food value of the cucumber is low, but its delicate flavour makes it popular for salads and relishes. Fresh cucumbers should be firm, well-shaped, and bright green in colour. They may be kept in refrigerated storage for about two weeks.