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Published In: Species Plantarum 2: 1013. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native


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1. Sicyos angulatus L. (bur cucumber)

Map 1631, Pl. 372 e

Plants monoecious annual vines with slender taproots. Stems to 5 m or more long, slender (1–2 mm in diameter), lacking glands at the tip, sparsely to moderately pubescent with slender, spreading, multicellular hairs, not roughened, at least some of the hairs usually minutely gland-tipped but the stems not strongly sticky, the tendrils branched. Leaves mostly long-petiolate, the petiole 1–5 cm long, densely hairy. Leaf blades 2–20 cm long, 3–22 cm wide, broadly ovate to nearly circular or somewhat kidney-shaped in outline, palmately shallowly to moderately 5-lobed with usually 3 major lobes and 2 minor lobes, the lobes broadly triangular, with sharply pointed tips (those of the basalmost lobes occasionally rounded) and broadly rounded (more than 90°) sinuses, cordate at the base, the margins otherwise sparsely to moderately and finely toothed, the surfaces sparsely to densely pubescent with minute, nonsticky hairs, especially those of the upper surface often minutely pustular-based and thus somewhat roughened to the touch. Flowers in dense clusters (pistillate) or in short but long-stalked racemes or clusters (staminate) 4–15 cm long in the leaf axils, the main stalk of the pistillate inflorescence 10–40 mm long, the clustered flowers sessile or with individual stalks to 0.5 mm long. Calyx lobes 1.0–2.5 mm long. Corollas 8–12 mm wide, saucer-shaped to broadly bell-shaped, the 5 lobes 3–5 mm long, white to cream-colored. Staminate flowers with the filaments fused into a tube (the anthers fused into a headlike mass). Pistillate flowers usually lacking staminodes, the ovary with 1 ovule, the stigma 3(4)-lobed. Fruits in dense, headlike clusters, thin-walled modified berries, dry and with the papery wall relatively closely enveloping the seed, indehiscent (the outer wall sometimes tearing irregularly with age), 1.2–1.8 cm long, more or less ovoid or ellipsoid, somewhat flattened, with a stalk 15–60 mm long, the surface yellowish green to olive-colored, covered with slender (often bristly), relatively stiff, straw-colored to pale yellow prickles 3–7 mm long, otherwise usually moderately pubescent with relatively long, fine, spreading, multicellular hairs. Seed 1, 7–10 mm long, 4–7 mm wide, elliptic-obovate to more or less elliptic in outline with a small pair of thickened basal areas, somewhat flattened, rounded to bluntly pointed at the tip, the surface otherwise relatively smooth, greenish brown to olive-colored. 2n=24. June–October.

Scattered nearly throughout the state but absent from most of the eastern half of the Glaciated Plains Division (eastern U.S. west to North Dakota and Texas; Canada; introduced in Europe, Asia). Banks of streams and rivers, bottomland forests, and bases, ledges, and tops of bluffs; also farmyards, railroads, roadsides, and disturbed areas.

This species is occasionally grown as an ornamental on arbors, but it is less attractive than Echinocystis. Although it is native to the eastern half of the country, it is listed as a noxious weed in Indiana and Delaware. Embryological studies have documented that S. angulatus is able to produce multiple parthenogenetic embryos in a single embryo sac (Dathan and Singh, 1990), but whether the species reproduces mostly sexually or apomictically is not known.



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