This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Introduced. Annual. Propagates by seeds.
Time of bloom: July to September. Seed-time: August to October. Range: Nova Scotia to Minnesota, southward to Florida. Habitat: Cultivated ground, roadsides, waste places.
At one time this weed was much helped in its wide distribution by seedsmen who recommended it as an ornamental plant. But for that purpose its beauty is too evanescent, and in grain field and garden it has proved itself extremely obnoxious because of the long vitality of its seeds; ground once fouled continues to produce plants for years, as cultivation brings the dormant seeds to surface light and warmth. (Fig. 198.)
Stems ten to twenty inches long, branched from the base, slender, rather weak and often reclining, covered with fine, bristly hairs. Leaves broadly heart-
Fig. 198. -Bladder Ket-mia (Hibiscus Trionum). X1/4 shaped in outline but deeply three-lobed, the middle lobe much the longest, the segments again cut and toothed. Flowers usually single in the upper axils, about two inches broad, pale sulfur-yellow with a purple center and fine purple vein-ing, the five broad petals often tinged with purple on the outer edge; they open only in sunshine and are usually closed before noon; calyx a thin, hairy, five-angled, membranous, and much inflated green "bladder," also delicately purple-veined; ovary five-celled, the cells usually three-seeded, the styles stigmatic at the summit, the column of stamens long, truncate at the top and bearing anthers below for much of its length. Involucral bracts linear, very hairy. Seeds triangular kidney-shaped, brown, roughened with pimples of lighter shade.
Prevent seed production by hand pulling or hoe-cutting while in first bloom. Ground where seeds have matured should be put to a well-tilled hoed crop.