Plants 4-110(-135) cm. Corms globose to elongate, 8-31 mm. Leaves: blade slightly curled transversely, linear, lanceolate, or seldom elliptic-lanceolate, 3-50 cm × 2-35(-50) mm. Inflorescences green or slightly purple at base, becoming entirely green after flowering, 4-110(-135) cm; floral bracts ovate to ovate-lanceolate, subulate, 3-8(-30) mm. Flowers 1-15(-25); dorsal sepal 15-31 × 5-18 mm; lateral sepals reflexed distally, 13-26 × 5-16 mm, apex apiculate to acuminate; petals 15-28 × 4-14 mm; lip 11-23 mm, dilated end of middle lobe same color as rest of flower (except for brushlike lamellae patch), typically anvil-shaped, seldom triangular or reniform, 9-21 mm wide; column 12-25 × 1-2 mm, distal end 6-10 mm wide; rostellum usually present. Capsules 13-30 × 5-10 mm. 2n = 26, 40, 42. Flowering Nov (s Fla.)--Aug (north). Acidic soils in fens, bogs, pine and oak savannas, grasslands, interdune swales; 0--1200 m; St. Pierre and Miquelon; Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis. At the northeastern edge of the range, tiny plants 4-20 cm have 1-5 deep magenta flowers, lips 13-18 mm with pale trichomes, and leaves 30-110 × 5-30 mm; they have been considered to be Calopogon tuberosus var. latifolius (H. St. John) B. Boivin. The variety has been reported in coastal bogs from Nova Scotia, the Magdalen Islands in the Gulf of St. Lawrence, Sable Island off Nova Scotia, Newfoundland, and Great Wass Island in the Gulf of Maine (C. A. Luer 1975; P. M. Catling and Z. Lucas 1987; L. M. Eastman 1988). Catling and Lucas found that plants corresponding to C. tuberosus var. latifolius represented the end of a continuum of variation and recommended against the recognition of the variety; those results were corroborated by DNA data (D. H. Goldman 2000). In contrast to the plants in the northeastern range, plants in the southern range of this variety can exceed 1 m in height and produce flowers close to 5 cm diameter.
Similar species: This is the only variety of Calopogon tuberosus in our area, and one should see the description of the species for full information.
Flowering: early June to August
Occurence in the Chicago region: native
Author: The Field Museum
From Flora of Indiana (1940) by Charles C. Deam
More or less frequent in its habitat throughout the lake area. It grows in the open in both peaty and marly springy places, in tamarack bogs, and in a moist, prairie habitat. In addition to the counties shown on the map it has been reported from Cass and White Counties.