Pennell has divided Chelone glabra into several varieties and forms, five of which he cites from Indiana. For the benefit of those who wish to study this species intensively I have listed these forms and given their distribution. The species and its forms grow in wet woods, springy places about lakes, along streams, and in marshes. I have [var. elatior] from only Clark County. I have [variety elongata] from Dubois, Jennings, and Spencer Counties and Kriebel has collected it in Lawrence County. [Variety linifolia] is the common form of the species in our area.
Erect, 5-8 dm, simple or branched above; lvs linear to lance-ovate, to 15 cm, acuminate, serrate with salient or ascending teeth, on a short indistinct petiole, or tapering to a sessile base; spikes 3-8 cm, subtended by scarcely reduced foliage-lvs; cor 2.5-3.5 cm, white, or partly greenish-yellow, or tinged with pink, or even purple toward the summit, the palate white-bearded; staminode green; 2n=28. Wet woods; Nf. to Minn., s. to Ga. and Ala. July-Sept. Highly variable, with ±evident regional trends of variation.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.