4. Cucurbita L.

Plants monoecious, annual or perennial vines. Stems 1–5 m or more long, relatively stout, 2–5 mm in diameter, coarsely roughened with stout, multicellular, pustular-based hairs, the tendrils branched. Leaves mostly long-petiolate, the petioles 3–12 cm long, lacking glands at the tip, coarsely roughened with stout, multicellular, pustular-based hairs. Leaf blades ovate to ovate-triangular or nearly circular in outline, unlobed or palmately shallowly to moderately or rarely deeply 3- or 5(7)-lobed, the lobes broadly triangular to more or less oblong to semicircular, rounded or bluntly to sharply pointed at the tip and with narrowly to more commonly broadly rounded or angled (mostly more than 90°) sinuses, the margins otherwise finely toothed, the surfaces moderately to densely roughened with mostly pustular-based hairs of varying length and thickness. Flowers solitary in the leaf axils or (in C. pepo) the staminate flowers occasionally in small clusters, the staminate flowers or flower clusters with longer stalks than those of the pistillate flowers. Calyx lobes 9–20(–30) mm long. Corollas 5–10 cm wide, deeply bell-shaped, 5-lobed, yellow to yellowish orange. Staminate flowers with the filaments fused into a tube except sometimes at the very base (the anthers fused into a headlike mass). Pistillate flowers with 3 staminodes, the hypanthium and calyx moderately to densely hairy, the ovary with numerous ovules per placenta, the stigma 3–5-lobed or more or less 6–10-lobed. Fruits solitary, modified berries 5–10 cm long (larger in some cultivated plants), with a pulpy, fibrous central portion, at least when young (drying out as the fruit matures in wild plants), and a relatively thin, hardened shell (the rind thicker and leathery in some cultivated plants), indehiscent, more or less spherical to ovoid or pear-shaped (variously shaped in cultivated plants), with a stalk 15–40 mm long, the surface glabrous at maturity, smooth (lacking prickles or warty outgrowths), green (variously colored in some cultivated plants), sometimes with irregular, longitudinal, light green or white stripes, becoming bleached to a yellow, tan, or ivory color, glossy or dull. Seeds numerous (more than 20), 6–10 mm long, elliptic to obovate in outline, flattened, sometimes with a pronounced, thickened rim, mostly rounded at the tip, the surface otherwise smooth, white, cream-colored, or tan, less commonly brown or black. About 13 species, native from North America to South America, introduced nearly worldwide.

The genus Cucurbita is of economic importance primarily for its edible and ornamental fruits but has also been used in crafts, as containers, and for soap (because some species produce appreciable amounts of saponins), among other things. Members of the genus have an extremely long history in the New World archaeological record (Nee, 1990) and were traded widely and transported throughout the Americas prior to European contact. Heiser (1979) has written eloquently and in great depth on the ethnobotany of the genus. Five different species are cultivated, including a great variety of types of pumpkins, acorn squashes, crooknecks, zucchinis, vegetable marrows, fordhooks, scallop squashes, and ornamental gourds. Common names such as squash and pumpkins are somewhat ambiguous as they have been applied to plants of more than one species.