Perennial herb to 1 m tall Stem: single or multiple from base, upright, hollow, unbranched, bristly-hairy. Leaves: opposite, stalkless, 8 - 18 cm long, 2 - 6 cm wide, lance-shaped to egg-shaped with base narrowing below middle, coarse and hairy above, less hairy beneath. Flowers: usually solitary in leaf axil. Sepals five, 9 - 12 mm long, linear, elongate, bristly along the margins. Corolla unequally five-lobed, greenish yellow, about 2 cm long, tubular or bell-shaped, base swollen, loosely hairy. Stamens five. Anthers yellow. Fruit: berry-like (drupe), orangish red, dry. There are three oblong stones inside each drupe.
Similar species: In the Chicago Region, Triosteum angustifolium differs from other Triosteum species by having bristly-hairy stems and hairless sepals with bristly margins.
Flowering: April to May
Habitat and ecology: Moist woods and low ground. Rare in the Chicago Region.
Occurence in the Chicago region: non-native
Etymology: Triosteum comes from the Greek words treis, meaning three, and osteon, meaning "a bone" (in reference to the three stones inside the fruit). Angustifolium means "narrow leaved."
More slender than the previous 2 spp., the stems 3-8 dm, sparsely and retrorsely setose-hispid with hairs 1.5-3 mm and also glandular with shorter hairs; lvs oblanceolate to obovate, the main ones 8-18 נ2-6 cm, narrowed below the middle to a sessile base, setose-strigose above with hairs 1-2 mm; fls usually solitary in the axils; sep 9-12 mm, hispid-ciliate, the back glabrous or pubescent; cor greenish-yellow, loosely villous; fr orange-red. Moist woods and low ground; May, June. Two vars.: Var. angustifolium, pubescence of the lower lf-surface none or restricted to the veins; lvs mostly about a fourth as wide as long; Conn. to s. Ont., O. and Mo., s. to N.C., Ala., and La. Var. eamesii Wiegand, lvs softly pubescent over the surface beneath, often obovate, ca half as wide as long; Conn. to N.J. and N.C.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.