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..
Perennial glabrous or pubescent herbs, with alternate sometimes punctate leaves, and rather large blue purple or white flowers, in panicles, cymes, or racemes. Calyx-lobes lanceolate or linear, little enlarged in fruit. Corolla tubular-funnel form or trumpet-shaped, crested or unappendaged in the throat, its lobes obtuse, imbricated, little spreading. Stamens inserted on the tube of the corolla, included, or scarcely exserted; filaments flattened, or filiform; anthers oblong or linear, obtuse. Ovary 4-divided; style filiform. Nutlets erect, coriaceous, wrinkled when mature, attached above their bases to the convex or nearly flat receptacle. [In honor of Prof. C. F. Mertens, a German botanist.]
About 40 species, natives of the northern hemisphere. Besides the following, many occur in the western part of North America. The species are called Smooth Lungwort. Type species: Mertensia pulmonarioides Roth. Corolla trumpet-shaped, not crested in the throat, the limb barely 5-lobed.
1. M. virginica.
Corolla funnelform-campanulate, crested in the throat, the limb manifestly 5-lobed. Stem-leaves ovate or ovate-lanceolate, acuminate.
2. M. paniculata.
Stem-leaves oblong or lanceolate, obtuse or acute.
3. M. lanceolata.
Pulmonaria virginica L. Sp. Pl. 135. 1753. Mertensia virginica DC. Prodr. 10: 88. 1846.
Glabrous; stem erect, or ascending, simple or sometimes branched, 1°-2° high, rather stout. Leaves oblong, oval, or obovate, pinnately veined, obtuse at the apex, 2'-5' long, the uppermost sessile, the lower narrowed into margined petioles; racemes short, corymb-like; pedicels 2"-6" long; flowers blue-purple, very showy, about 1' long; calyx-lobes oblong-lanceolate, obtusish, 1" long or less; corolla trumpet-shaped or nearly salverform, its tube cylindric, a little expanded above, longer than the 5-lobed plaited limb, pubescent at the base within, not crested in the throat; disk with two opposite linear lobes; filaments filiform, much longer than the anthers; nutlets not shining, rounded.
In low meadows and along streams, southern Ontario to New Jersey and South Carolina, Minnesota, Nebraska and Kansas. Blue bells. March-May.
Roughish-pubescent, dark green; stem erect, branched above, l 1/2°- 3° high, the branches slender. Leaves thin, pinnately veined, those of the stem ovate or ovate-lanceolate, acuminate at the apex, narrowed at the base, 2'-5' long, the lower narrowed into slender petioles; basal leaves ovate, rounded or cordate at the base; racemes several-flowered, panicled; pedicels filiform,4"-10" long; flowers purple-blue, 6"-7" long; calyx-lobes lanceolate, acute; corolla tubular-campanulate, crested in the throat, the tube about twice as long as the calyx and exceeding the 5-lobed limb; filaments flattened, slightly longer than the anthers; style filiform, usually somewhat exserted; nutlets rounded.
In woods or thickets, Hudson Bay to Alaska, south to Michigan, Nebraska, Idaho and Washington. July-Aug.
Glabrous or somewhat hirsute; stem simple or branched, slender, 6-18' high. Leaves papillose, indistinctly veined, light green, the upper lanceolate, acute, sessile or slightly clasping at the base, the lower oblong or oblanceolate, obtuse, 3-4' long, narrowed into margined petioles; racemes few-flowered, usually panicled; flowers blue, 5"-6" long; pedicels 3"-7" long; calyx-lobes lanceolate, obtuse, or acutish; corolla tubular-campanulate, the tube longer than the calyx and longer than the 5-lobed limb, hairy at the base within, the throat crested; filaments a little longer than the anthers; style filiform, scarcely exserted.
In thickets, western Nebraska to Manitoba, Wyoming, Idaho and New Mexico. Races differ in amount or absence of pubescence and in width of leaves. June-Aug.