17. Melothria Linnaeus, Sp. Pl. 1: 35. 1753; Gen. Pl. ed. 5, 21. 1754.
Melonette [Greek melothron, ancient name for some fruiting vine, probably Bryonia] Melonette [Greek melothron, ancient name for some fruiting vine, probably Bryonia]
Plants herbs, perennial [annual], monoecious, climbing, trailing, or creeping; stems <annual>, glabrous or hispid [pilose]; roots tuberous; tendrils unbranched. Leaves: blade ovate-reniform, cordate-pentangular, suborbiculate to depressed-ovate, ovate, ovate-triangular, or lanceolate-hastate, subentire or shallowly to deeply palmately 3–5-lobed or -angled, lobes deltate to shallowly triangular, margins denticulate [dentate, shallowly sinuate, or subentire], surfaces eglandular. Inflorescences: staminate flowers 2–6 in axillary racemes or corymboid to subumbelloid clusters; pistillate flowers solitary, usually in same axils as staminate; bracts absent. Flowers: hypanthium campanulate; sepals 5, triangular to ovate, <straight>; petals 5, connate 1/2 length, yellow or orange-yellow [white or pale orange], oblong to ovate-oblong or obovate-oblong, 1.5–2[–3.5] mm, glabrous or villosulous, corolla rotate to campanulate-rotate. Staminate flowers: stamens 3; filaments inserted near hypanthium base or near mid tube, distinct; thecae distinct, oblong, connective broadened; pistillodes present, <nectariferous>. Pistillate flowers: ovary 3-locular, globose to ovoid or fusiform; ovules ca. 15–20 per locule; style 1, short-columnar; stigmas 3, 2-lobed; staminodes 3 or absent. Fruits pepos, greenish, often striped or mottled, apparently usually maturing yellow to orange or purplish black, usually ellipsoid to ovoid, sometimes subglobose to globose, <(0.8–)1–2.5 cm>, smooth, <glabrous>, indehiscent. Seeds 30–60, ovoid to ellipsoid, compressed, not arillate, margins not differentiated, surface smooth, <white-sericeous>. x = 12.
Species 12 (1 in the flora): United States, Mexico, West Indies, Central America, South America; introduced in Asia.
The concept of Melothria was considerably narrowed by C. Jeffrey (1962), leaving the genus an entirely New World taxon characterized by long-peduncled fruits and staminate racemes, compressed seeds, and three stamens per flower, two of which are 2-thecous and the other 1-thecous. The segregated (or revived) genera Mukia Arnott (four species), Solena Loureiro (one species), and Zehneria Endlicher (30 species) are from the Old World tropics.