Perennial herb Stem: mostly below the soil surface, very short. Leaves: forming a basal rosette, with a flattened stalk 1.5 - 5 cm long and unevenly fringed stipules 4 - 6 mm long. The blades are 4 - 10 mm long, rounded and often broader than long, covered with reddish glandular hairs on the upper surface with peripheral hairs much longer than the center hairs. Flowers: 4 - 7 mm across, with five sepals 4 - 5 mm long and five white to pink petals. Fruit: a capsule containing shiny light brown, 1 - 1.5 mm long, elongate, longitudinally grooved seeds. Flowering stem: (scape) arising from base of plant, 7 - 35 cm long, hairless, bearing three to fifteen flowers usually borne on a single side. Winter bud-like structures: (hibernacula) each made of a spherical cluster of undeveloped leaves (primordia). These strucutres protect the plant through the winter, when the leaves and roots often die back.
Similar species: Drosera intermedia and Drosera rotundifolia can be easily distinguished by a few key features. Most leaves of D. intermedia form a rosette, but some are also borne on nodes above the rosette. The leaf blade is oblong spatula-shaped and longer than broad, and the seeds are oblong and warty.
Flowering: late June to late August
Habitat and ecology: This species is characteristic of bogs, but will also grow in disturbed areas with moist, sandy soil.
Occurence in the Chicago region: native
Notes: This carnivorous species uses traps in the spring and summer to catch insects. Long peripheral glandular hairs secrete a sticky substance to trap insects. The hairs then bend inward while the leaf slowly folds, placing the prey on the shorter center glands. These center glands secrete digestive enzymes to break down the insect. Charles Darwin discussed Drosera rotundifolia in great detail in the book Insectivorous Plants. It has the widest distribution of the sundews, and is found in Europe, Asia, South Africa, South America and North America. Drosera intermedia and D. rotundifolia are known to hybridize.
Etymology: Drosera comes from the Greek word droseros, meaning dewy, referring to the dewy look of the gland-tipped hairs found on the leaves. Rotundifolia refers to the rounded leaves of the plant.
Petioles 1.5-5 cm, flat, glandular-hairy; lf-blades 4-10 mm, broader than long, much shorter than the petiole; stipules 4-6 mm, adnate, fimbriate along the upper half, scape glabrous, 7-35 cm, with 3-15 fls 4-7 mm wide; sep 4-5 mm; pet white to pink, spatulate, longer than the sep; seeds light brown, lustrous, 1-1.5 mm, sigmoid-fusiform, finely and regularly striate longitudinally; 2n=20. Common in bogs and swamps; circumboreal, in Amer. s. to S.C., Ga., Tenn., Ill., and Calif. June-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.