Plant: annual herb; 0.5 m tall, the stems sparsely stellate-pubescent to glabrate Leaves: deeply 3-parted, each lobe pinnately divided, very sparsely pubescent, 3-5 cm long Flowers: axillary, the pedicels 1-3 cm long; bracts of involucel 4-7 mm long; calyx 15-20 mm long, inflated and membranous with dark-pigmented veins; petals 2-2.5 cm long, yellow with a prominent purple spot at base Fruit: FRUITS ovoid capsules, included in calyx, hispid; SEEDS 2 mm long, warty Misc: Cultivated plant, doubtfully established; ca. 2150 m (7000 ft); Aug REFERENCES: Fryxell, Paul A. 1994. Malvaceae. J. Ariz. - Nev. Acad. Sci. Volume 27(2), 222-236.
Annual herb 30 - 50 cm tall Stem: ascending, slender, branching, and hairy. Leaves: alternate, long- stalked, hairy, deeply three parted (nearly to base) with segments fairly narrow, oblong or egg-shaped, and very coarsely toothed. Flowers: axillary, stalked, ephemeral, pale yellow with purple center, relatively small (3 - 8 cm diameter), with five spreading petals, and five sepals, which are immediately subtended by more than ten, slender, linear bristly bractlets. Sepals: five, but fused for over half their length, then separating into five widely-triangular lobes, which enlarge in fruit to enclose the capsule. The calyx as a whole has very conspicuous veins, which have swollen-based, spreading, stiff, straight hairs along their length. Petals: five, pale yellow with purple base, 1.5 - 4 cm long, widely spreading, narrowest at base and widening to shallowly toothed to slightly wavy tips. The petals are expanded for only a few hours. Stamens: numerous, but filaments fused into a long tube, with separate anthers all along the tube sides, and five teeth at top of the tube. Pistil: enclosed by the stamen tube, with one five-chambered superior ovary, five fused styles coming up through center of stamen tube and extending beyond it before branching above into five, obvious, rounded stigmas. Fruit: long-stalked, five-chambered, many-seeded, stiff bristly-hairy, somewhat rounded capsules enclosed by the persistent, greatly inflated, five-angled calyx. Each capsule chamber contains several, finely warty seeds, which are released as the top of the capsule opens outward and lengthwise downward.
Similar species: Hibiscus trionum is unlike our other species in this genus since it is an annual with ephemeral flowers that are only fully open for a few hours, the flowers are pale yellow and relatively small with spreading petals, and the leaves are very deeply three-lobed with the narrow lobes coarsely toothed.
Flowering: June to October
Habitat and ecology: A common weed of cultivated ground, found in gardens, cornfields, and similar habitats.
Occurence in the Chicago region: non-native
Notes: This plant is native to southern Europe and is a common weed in North America.
Branching, hairy annual 3-5 dm; lvs long-petioled, deeply 3-parted, the segments oblong to obovate, coarsely serrate or lobed; cal conspicuously veined, hispid on the nerves with spreading simple hairs from swollen bases; pet 1.5-4 cm, pale yellow with purple base, expanded only a few hours; mature cal inflated, 5-angled, enclosing the hirsute fr; seeds finely verrucose; 2n=28, 56. Native of s. Europe; fields, roadsides, and waste places from N.S. to Minn., s. to Fla. and Tex. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
An obnoxious weed in rather sandy soil in cultivated grounds in many parts of the state, especially in the glaciated area. I can recall the time when I rarely saw it but now in certain areas it forms a complete stand in cornfields. Although it is an annual, when once established, it is difficult to exterminate on account of its numerous seeds and their unusual viability.