From Flora of Indiana (1940) by Charles C. Deam

Our only specimen is from railroad ballast about a quarter of a mile east of Dana in Vermillion County. Common here in one place but not noted again between Dana and Hillsdale, a distance of 6 miles.

Stem erect, 4-8 dm, bearded at the nodes and usually sparsely spreading- bristly on the angles; lvs subsessile, narrowly oblong, 3-7 cm, acute or acuminate, sharply serrate, usually acute at base, glabrous; bracts ovate or lance-ovate, denticulate and sparsely ciliate; cal-tube 3-4 mm, glabrous or commonly sparsely villous, the lobes glabrous, deltoid, 2.3-3.4 mm, more than half as wide. Moist soil; Pa. to Io., s. to Ga. and Mo. July-Sept. (S. hyssopifolia var. ambigua; S. ambigua (A. Gray) Britton, not Sm.; S. grayana)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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