This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Stachys atlantica Britton, Man. 792. 1901.
Perennial, glabrous or with a few hairs at the nodes of the stem, weak, diffuse, 8'-16' long. Leaves thin, oblong or linear-oblong, obtuse or obtusish at the apex, narrowed, or the upper sometimes rounded at the base, remotely denticulate or entire, spreading, 2' long or less, 2"-5" wide; fruiting calyx glabrous, broadly campanulate, about 2 1/2" long, its teeth triangular-ovate, acuminate, more than half as long as the tube; corolla purplish.
Stachys hyssopifolia var. ambigua A. Gray, Syn. Fl.
Perennial; stem slender, erect, retrorsely hispid, at least below, simple or sparingly branched, 1°-2° high. Leaves oblong, oblong-lanceolate, or linear, pubescent or glabrate, acuminate or acute at the apex, narrowed at the base, 2"-10" wide, 1'-3' long, serrulate; clusters in a terminal rather dense spike, and usually also in the upper axils; calyx more or less hirsute, 2 1/2" long, its lanceolate-subulate teeth more than one-half as long as the tube; corolla nearly as in S. hyssopifolia.
In moist soil, Massachusetts to Pennsylvania, Georgia, Wisconsin and Kentucky. July-Aug.
Stachys arenicola Britton, Man. 792. 1901.
Perennial, very densely pubescent, 1 1/2°-3° high. Leaves lanceolate, narrowed at the base, sessile, finely crenate-dentate, acuminate, 2 1/2'- 4' long, the upper much smaller; upper bracts little longer than the flowers; calyx-teeth subulate-acicular, about as long as the tube; corolla about 5" long.
In sandy soil, southern New York to Illinois and Michigan. July-Sept.
Stachys latidens Small; Britton, Man. 793. 1901.
Perennial; stem glabrous almost to the inflorescence, erect, 1°-2 1/2° tall, mostly simple, slightly rough on the angles. Leaves thin, various, the lower oval or ovate to oblong, 1 1/2'- 4' long, the upper longer, narrower, oblong-elliptic to lanceolate, acute or acuminate, all crenate-serrate with rather small teeth, rather abruptly narrowed or subcordate at the base, short-petioled; inflorescence closely pubescent, the clusters few; calyx minutely pubescent, often sessile, 2 1/2"-2" long, the tube campanulate, the teeth triangular, very short; corolla about 5" long, purplish.
On mountain slopes and summits, Virginia to North Carolina and Tennessee. June-Aug.