3. Cucumis L.

(Kirkbride, 1993)

Plants monoecious, annual (perennial elsewhere) vines with taproots. Stems 1–3 m or more long, relatively stout (2–4 mm in diameter, at least toward the base), coarsely roughened with stout, multicellular, pustular-based hairs, the tendrils unbranched. Leaves mostly long-petiolate, the petioles 1–9 cm long, lacking glands at the tip, coarsely roughened with stout, multicellular, pustular-based hairs. Leaf blades ovate to ovate-triangular or nearly circular to somewhat kidney-shaped in outline, palmately shallowly to moderately (3)5-lobed, often with 3 major lobes and 2 minor lobes, the lobes broadly triangular to more or less oblong to semicircular, rounded or sharply pointed at the tip and with broadly rounded (mostly more than 90°) sinuses, the margins otherwise finely toothed, the surfaces moderately to densely roughened with a mixture of minute and longer, pustular-based hairs. Flowers solitary or in small clusters in the leaf axils, the clusters with the main stalk absent or to 25 mm long, the individual flowers with stalks 1–8 mm long. Calyx lobes 1–3 mm long. Corollas 0.5–4.0 cm wide, bell-shaped or those of the staminate flowers sometimes saucer-shaped, 5-lobed, yellow to orangish yellow. Staminate flowers with the stamens distinct. Pistillate flowers with 3 staminodes, the ovary with numerous ovules per placenta, the stigma 3(–6)-lobed. Fruits solitary or less commonly (in C. sativus) in clusters of 2 or 3, juicy berries more than 5 cm long, the rind thin or thick, often somewhat leathery (but not hardened), indehiscent, variously shaped, with a stalk 3–25 mm long, the surface often hairy and sometimes with blunt, soft prickles when young, usually glabrous at maturity, smooth or sparsely warty (not spiny, but the bases of shed prickles sometimes still apparent) or with a dense network of ridges, green, pale grayish green, greenish yellow, or tan, sometimes with irregular stripes, glossy or dull. Seeds numerous (more than 20), 7–10 mm long, oblong-elliptic to oblong-obovate in outline, flattened, rounded to sharply pointed at the tip, the surface otherwise smooth, white or light yellow. About 32 species, native to Africa, Asia, south to Australia, introduced nearly worldwide.

The genus Cucumis is economically important for its edible fruits. The two most important species are those treated below as escapes from cultivation, the cantaloupes/muskmelons and the cucumbers/pickles. However, a third species is becoming popular in this country. Cucumis metuliferus E. Mey. ex Naudin was developed from plants native to Africa and southwestern Asia. It produces an oblong-ellipsoidal fruit 6–15 cm long whose yellowish orange to reddish orange surface has scattered, coarse, conical prickles and green pulp. Sold under the names horned melon and horned cucumber, the flavor of the cultivated strains is relatively bland (the wild relatives of most cultivated melons have a very bitter flavor), but the fruit has a long shelf life in supermarkets and its unusual appearance has presumed ornamental value.