Perennial herb 30 cm - 0.6 m tall Leaves: opposite, stalkless, 3 - 6 cm long, 1 - 3 cm wide, oblong to egg-shaped or elliptic with a more or less heart-shaped base and a rounded to notched tip, non-toothed, covered with translucent glands and dark dots beneath. Flowers: borne in axillary or terminal clusters, with 3 - 5 mm long sepals that are elliptic to oblong with a rounded to blunt tip, five pinkish petals 5 - 8 mm long, 0.5 - 1.5 mm long styles, and nine stamens forming three groups of three that alternate with three glands. The flowers usually remain closed, especially in sunlight. Fruit: a three-chambered capsule, purplish, 7 - 12 mm long, egg-shaped to cylindrical, narrowing abruptly at the tip, vertically ribbed, many-seeded. Stems: erect, branching near the top or remaining unbranched.
Similar species: Triadenum virginicum has 5 - 8 mm long sepals at maturity, pointed sepal tips, and styles 2 - 3 mm long.
Flowering: mid July to early September
Habitat and ecology: Locally common in moist areas such as bogs, marshes, moist calcareous sand, and very limy (marly) fens.
Occurence in the Chicago region: native
Etymology: Fraseri was named after Scottish plant collector John Fraser (1750 - 1811).
Much like no. 1 [Triadenum virginicum (L.) Raf.]; sep elliptic or oblong, obtuse or rounded, 3-5 mm; pet 5-8 mm; fr ovoid or cylindric, 7-12 mm, rather abruptly narrowed to the 0.5-1.5 mm styles. Bogs, marshes, and wet shores; Nf. and Que. to Minn., s. to Conn., N.Y., O., n. Ind., and Neb., and in the mts. to W.Va. July, Aug. (Hypericum f.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.