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, triangular to rounded, up to 3 mm long petal lobes, which often end in a short point. While the separate tip of the petal lobes is about 3 mm long, it is still 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. The petal tube is whitish at its base, but 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), usually unbranched, and hairless or occasionally covered with short fuzzy hairs. Seeds: flattened, winged, and smooth.
Similar species: Gentiana andrewsii var. dakotica is very similar to the common, typical variety, G. andrewsii var. andrewsii, but that variety has less smaller petal lobes, with the free point scarcely even 1 mm long, and the stems are always completely hairless. Two other species of closed gentians in our area which may be confused with G. andrewsii var. dakotica include G. alba, which differs by having whitish flowers, and completely hairless leaf edges and sepal lobes; and G. saponaria, which 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: mid-August to October
Habitat and ecology: Low, moist, open ground, but extremely rare in our area.
Occurence in the Chicago region: native
Notes: In our area, the two varieties of G. andrewsii are very similar. It is west of the Mississippi River where G. andrewsii var. dakotica becomes more easily distinguished (Pringle 1967). It appears the differentiation between the two varieties may be more a matter of geography rather than anything visibly observable from morphology.
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. Dakotica refers to the plant occurring in the western United States.