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..
Lobelia amoena Michx. FI. Bor. Am. 2: 152. 1803. Lobelia amoena glandulifera A. Gray, Syn. Fl. 2: 4. 1878.
Nearly glabrous throughout, perennial; stem simple, slender, leafy, 1°-4° high. Leaves thin, ovate to oblong-lanceolate, narrowly oblong, or oval, repand-dentate or denticulate, the lower petioled and mostly obtuse, 2-6' long, the upper sessile, acute or acutish, smaller; flowers blue, racemose, nearly 1' long; bracts narrow and small, or the lower foliaceous, glandular; pedicels 1"-2i" long; calyx-lobes linear-subulate, acuminate, glabrous, glandular, elongated, the sinuses usually not auricled; corolla-tube 5"-7" long, 1 1/2"-2" thick; larger anthers glabrous, or puberulent at the tip; lobes of the larger lip of the corolla broadly ovate to oval, obtuse, glabrous.
In swamps, Delaware to Florida and Alabama. July-Sept.
L. elongata Small, Fl. SE. U. S. 1144. 1903.
Perennial, at least by offsets, glabrous or nearly so; stem simple, 1°-3° tall, commonly wand-like. Leaves rather few, erect or ascending, linear or nearly so, 3/4'-4' long, mostly acute, serrate or dentate-serrate with gland-tipped teeth, sessile or narrowed into petiole-like bases; flowers deep-blue in rather closely flowered, but not densely flowered, one-sided racemes 4'-12' long; bracts linear to lanceolate, serrate with gland-tipped teeth, the lower ones sometimes surpassing the corollas; calyx-lobes elongate, linear-subulate or linear-setaceous, entire, as long as the corolla or shorter, without auricles at the sinuses; corolla-tube s"-8" long, lobes of the lower lip oval or ovate, glabrous.
In low grounds or swamps, Virginia to Florida and Louisiana. Aug.-Oct.
Lobelia puberula Michx. Fl. Bor. Am. 2: 152. 1803.
Perennial, densely and finely puberulent all over, slightly viscid; stem simple, or rarely with a few branches, stout or slender, leafy, 1°-3° high. Leaves oval, oblong, ovate, or obovate, 1'-2' long, rather thick, the lower petioled, all obtuse or the uppermost acute, denticulate or crenate-dentate, the teeth often glandular; flowers blue, 8"-10" long, in long spike-like racemes; lower bracts, or sometimes all of them, foliaceous, glandular; pedicels very short; calyx hirsute or pubescent, its lobes narrowly lanceolate, elongated, usually with small short rounded auricles at the sinuses; corolla-tube about 5" long, 1"-1 1/2" thick, the lobes of its larger lip broadly ovate, glabrous; larger anthers minutely bearded.
In moist sandy soil, southern New Jersey to Florida, Illinois, Iowa, Kansas and Texas. Ascends to 3500 ft. in North Carolina. Aug.-Oct.