Melothria is a genus of flowering plants in the family Cucurbitaceae (the gourd family, order Cucurbitales), native to the Americas from the southeastern United States south to Argentina. The genus comprises small, mostly climbing or scrambling annual and perennial vines, characterised by slender tendrils, lobed or angled leaves, small yellow flowers, and diminutive cucumber-like fruits that are typically green with pale stripes when immature and darken to black or deep purple at maturity.
The genus has undergone significant taxonomic revision: a number of Old World species once placed in Melothria have been reassigned to the closely related genus Cucumis, narrowing Melothria to an essentially New World group. Within its native range it occupies disturbed ground, forest edges, roadsides, and moist thickets.
The best-known member of the genus in cultivation is Melothria scabra, the Mexican sour gherkin or mouse melon, a small-fruited cucurbit grown for its grape-sized fruits that resemble miniature watermelons and carry a mild cucumber flavour with a faint sour note. The widespread wild species Melothria pendula, the creeping cucumber, occurs across the southeastern United States and into tropical America and is occasionally eaten as a vegetable when immature, though ripe fruits are reported to have a laxative effect.
Distribution
Melothria is native to the Americas, ranging from the southeastern United States south to Argentina. Several species have been introduced beyond this native range, including in parts of Africa. Old World taxa once assigned to the genus have since been transferred to Cucumis.
Taxonomy Notes
Melothria belongs to the family Cucurbitaceae, order Cucurbitales. The genus has been substantially revised: numerous Old World species formerly included in Melothria have been reassigned to Cucumis, restricting the genus to the New World. GBIF accepts Melothria at genus rank within Cucurbitaceae.
Cultivation
Melothria scabra (mouse melon / Mexican sour gherkin) is the primary cultivated representative of the genus. It is grown as a warm-season annual, preferring well-drained soil, full sun, and a trellis or other support for its slender vines. Fruits are harvested small (grape-sized) for the best flavour and texture; the plant is valued for its high productivity and ornamental appearance.
