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..
Pentstemon erianthera Pursh, Fl. Am. Sept. 737. 1814. Pentstemon cristatus Nutt. Gen. 2: 52. 1818.
Puberulent below, glandular-villous and viscid above; stem rather stout, leafy, 6' - 18' high. Leaves firm, entire or repand, the lower and basal ones oblong or spatulate, obtuse or acutish, 2' - 4' long, narrowed into margined petioles, the upper sessile or somewhat clasping, acute or acuminate; thyrsus dense, narrow, leafy-bracted; flowers almost sessile; calyx-segments linear-lanceolate, acuminate, villous when young; corolla about 1' long, rather abruptly dilated above, red or purple, its lower lip villous within; sterile filament densely long-bearded.
On plains and bluffs, South Dakota to Manitoba, Montana, Nebraska and Nevada. May-July.
Pentstemon albidus Xutt. Gen. 2: 53. 1818.
Stems puberulent below, densely glandular-pubescent above, rather stout, 6'-10' high. Basal and lower leaves spatulate or oblong, obtusish, mostly entire, the upper lanceolate or oblong, sessile, denticulate, acute or acuminate, 1 1/2' - 2 1/2' long, 3"-6" wide; thyrsus narrow, raceme-like, leafy-bracted, interrupted; calyx-segments lanceolate, acuminate, viscid, one-half as long as the corolla-tube; corolla white or nearly so, 8"- 10" long, funnel form, the tube gradually dilated upward, the limb nearly equally 5-lobed, the lobes spreading; sterile filament slightly bearded with short hairs.
On plains, Minnesota and South Dakota to Assini-boia, Colorado, Nebraska and Texas. June-Aug.
2: 300. 1789. P. Pentstemon Britt. Mem.Torr. Club 5: 291. 1894.
Glabrous, except the somewhat glandular-pubescent inflorescence; stem slender, 2°-3° high. Basal and lower leaves oblong or oval, obtuse, 3'-6' long, narrowed into margined petioles, denticulate; upper leaves sessile or slightly clasping, acute, oblong, or lanceolate, denticulate; thyrsus open, usually many-flowered; flowers nearly sessile; calyx-segments lanceolate, acute, short; corolla purple or purplish, 8"- 10" long, the tube gradually enlarged above, the throat wide open, scarcely or not at all bearded, the lobes spreading; sterile filament thinly bearded for about one-half its length, or more densely bearded above.
Woods and thickets, Pennsylvania to Florida, Kentucky and Louisiana. Occasionally escaped from cultivation further north and east. May-July.