Perennial herb 10 cm - 1.2 m tall Leaves: opposite, stalkless, medium green, 3 - 16 cm long, 1 - 5 cm wide, more or less lance-shaped, three- to five-nerved, non-toothed, but with rough-bristly or prickly-hairy edges. The leaf shape changes along the stem, with the upper leaves being lance- to egg-shaped; the middle leaves being more narrow and grading toward elliptic; the lower leaves being more oblong, and much smaller than those above; and the lowest leaves reduced to scales. Inflorescence: of one to twenty-five, often stalkless, erect flowers clustered at the the stem apex, and often also in the axils of the upper one to six leaves, or additionally at the ends of short branches. The terminal inflorescence is normally subtended by two pairs of large, leaf-like bracts. Flowers: bluish with white markings, 3 - 4.5 cm long, radially symmetric, club-shaped, closed, and subtended by a pair of linear to inversely lance-shaped bracts. Sepals: five, but fused into a 0.8 - 1.4 cm long, hairless tube, then separating into 0.2 - 1.5 cm long, 0.8 - 6.4 mm wide, lance-shaped lobes with rough-bristly edges. Petals: five, but fused with longer, whitish membranes (plaits) between the erect, thin, narrow, abruptly short pointed petal lobes. The separate portion of the petal lobes is 1 - 3 mm long, and is typically surpassed by the 1 - 4 mm long, 2.5 - 7 mm wide, fairly erect, flat-topped, fringe-tipped plaits, which form most of the top of the flower. While the petal tube is whitish at its base, it becomes more colored with blue upwards (changing to blue-violet with age), and the nearly white alternating plaits are usually pale blue where they are fused to the petals. Stamens: five, attached to the inside of the petal tube, the filaments 0.8 - 1.2 cm long, with the anthers fused together. Pistil: with a single-chambered, superior ovary; a short, stout style; and a two-lobed stigma. There is a whorl of nectar glands present around the base of the ovary, though they are not attached to the fused petal tube base. Fruit: a single-chambered, two-valved, elliptic capsule containing numerous seeds. Stems: one to twenty, erect (occasionally somewhat decumbent), typically hairless, and usually unbranched. Seeds: flattened, winged, and smooth.
Similar species: Gentiana andrewsii is represented by two varieties in the Chicago Region, which are linked below. In addition, there are two other species of closed gentians in our area with which G. andrewsii or its varieties may be confused. Gentiana alba differs by having whitish flowers, and completely hairless leaf edges and sepal lobes. Gentiana saponaria has much narrower leaves (under 2 cm wide) with shorter, not long pointed tips, and the petal lobes are about as long as the fused plaits.
Flowering: August to October
Habitat and ecology: Occasional in damp prairies, wet meadows, and other moist open ground.
Occurence in the Chicago region: native
Notes: The only observed pollinators for this gentian are bumblebees, which appear to be the only insects strong enough and smart enough to open the closed flowers (Costelloe 1988).
Etymology: Gentiana is named after Gentius, king of Illyria, who supposedly discovered a medicinal value for the yellow gentian. Andrewsii is named after the English botanical artist Henry C. Andrews.
Stems 3-10 dm, glabrous, usually simple; lvs lanceolate or lance-ovate, to 15 נ4 cm, scabro-ciliolate; fls in terminal clusters and often sessile in the upper axils or on short branches; cal-tube glabrous, the lobes mostly lanceolate, sometimes broader, 4-10(-15) mm, finely scabro-ciliolate; cor whitish below, generally blue upwards, 3-4.5 cm, closed, the thin lobes adnate to the plaits nearly to the narrow, truncate and usually apiculate summit, the free tip scarcely 1 mm, the plaits dilated above, fimbriate, evidently exceeding the cor-lobes and forming most of the summit of the cor; anthers connate; 2n=26. Moist prairies, open woods, and swamps. July-Oct. The var. andrewsii, as principally described above, occurs from N.H. and s. Que. to Md., and W.Va., w. to s. Man., Minn., and Mo., and sporadically to Wyo. W. of the Mississippi R. it passes into the var. dakotica A. Nelson, found mainly from Minn. to Sask., s. to Mo. and Kans. Var. dakotica, which may reflect introgression from no. 2 [Gentiana puberulenta J. S. Pringle], has better developed cor-lobes than var. andrewsii, these triangular to rounded, often mucronate, to 3 mm, and it occasionally has papillate-puberulent stems.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.