Drosera intermedia Hayne
Family: Droseraceae
Drosera intermedia image
Paul Rothrock  
Perennial herb Stem: 1 - 8 cm long, often partly below the soil surface. Leaves: forming a rosette, with some leaves arising at nodes above the rosette, with hairless stalks 2 - 5 cm long and 2 - 5 mm long stipules dividing into several segments. The blades are green to reddish (increasingly red in sunlight), 0.8 - 1.5 cm long, 4 - 5 mm wide, oblong spatula-shaped to inversely egg-shaped, covered with reddish glandular hairs on the upper surface with peripheral hairs much longer than the center hairs. Flowers: with five sepals 3 - 4 mm long and five white petals 4 - 5 mm long. Fruit: a capsule containing reddish brown, 0.7 - 1 mm long, oblong, blunt ended, and warty seeds. Flowering stem: (scape) arising from base of plant, 1 - 8 cm long, with 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. The leaves of D. rotundifolia form a basal rosette, and the leaf blade is rounded and often slightly broader than long. The seeds taper at both ends and are longitudinally grooved.

Flowering: mid July to mid September

Habitat and ecology: This species is characteristic of bogs, but will also grow in excavated areas with exposed sand close to the water table.

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. Vegetative apomixis occurs frequently in this species. During vegetative apomixis, the flower sepals, petals, stamens, and pistil are replaced by tiny plantlets which are capable of rooting to form new plants. This tends to occur most often when flower buds are initiated during springs with cold nights and warm days. 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. Intermedia means intermediate.

Author: The Morton Arboretum

From Flora of Indiana (1940) by Charles C. Deam
Less frequent than the preceding species [Drosera rotundifolia] and found in the open in moist, sandy soil among sedges or in mossy places on the wet borders of lakes, and in sphagnum bogs.


Indiana Coefficient of Conservatism: C = 10

Wetland Indicator Status: OBL

Stem 1-8 cm, with lvs in a rosette or also at intervals for several cm; petioles 2-5 cm, glabrous; lf-blades oblong-spatulate to obovate, 8-20 cm נ4-5 mm, with long glandular hairs on the upper side; stipules adnate for 1 mm, then breaking into several setaceous segments 2-5 mm; sep 3-4 mm; pet 4-5 mm, white; seeds reddish-brown, oblong, 0.7-1 mm, blunt at the ends, densely and irregularly covered with long papillae; 2n=20. In wet places and shallow water; interruptedly circumboreal, in Amer. from Nf. to Fla., w. to Minn., Ill., Tenn., and Tex. July, Aug. (D. longifolia, in part) Hybridizes with no. 2 [Drosera rotundifolia L.].

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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