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..
[Physostegia Benth. Lab. Gen. & Sp. 504. 1834.]
Erect perennial glabrous or puberulent herbs, with serrate, dentate or entire leaves, and large or middle-sized, bracted purple violet, pink or white flowers in terminal spikes, or spike-like racemes. Calyx campanulate or oblong, membranous, swollen and remaining open in fruit, faintly reticulate-veined and 10-nerved, equally 5-toothed. Corolla much longer than the calyx, its tube gradually much enlarged upward, its limb strongly 2- lipped; upper lip concave, rounded, nearly or quite entire; lower lip spreading, 3-lobed, the middle lobe commonly emarginate. Stamens 4, didynamous, ascending under the upper lip of the corolla, the lower pair the longer; filaments pubescent; anthers all alike, 2-celled, the sacs nearly parallel, the margins of their valves commonly spinulose or denticulate. Ovary 4-parted. Nutlets ovoid-triquetrous, smooth. [Greek, dragon-head.]
About 7 species, natives of North America, known as False Dragon-head or Lion's-heart. Type species: Dracocephalum virginianum L.
Flowers 9" long, or more; leaves firm. Spike dense, many-flowered.
1. D. virginianum.
Spike loose, few-flowered; leaf-serrations mostly blunt.
2. D. denttculatum.
Flowers 5 -7" long; leaves thin.
Spike loose; 4'-8' long; leaves few and distant.
3. D. intermedium.
Spike dense,: -4 long; stem leafy.
4. D. Nuttallii.
Dracocephalum virginianum L. Sp. Pl. 594. 1753.
Physostegia virginiana Benth. Lab. Gen. & Sp. 504. 1834.
Stem erect or ascending, rather stout, simple or branched above, 1°-4° tall. Leaves firm, lanceolate, oblong-lanceolate, or linear-lanceolate, acuminate at the apex, sharply serrate or serrulate, narrowed at the base, the upper all sessile, 2'-5' long, 2"-7" wide, the lowest petioled; bracts lanceolate, shorter than the calyx; spikes dense, becoming 4'-8' long in fruit, many-flowered; flowering calyx campanulate or somewhat turbinate, its teeth ovate, acute, about one-half as long as the tube; fruiting calyx oblong, 4"-s" long, the teeth much shorter than the tube; corolla pale purple or rose, about 1' long, often variegated with white, temporarily remaining in whatever position it is placed.
Physostegia Digitalis Small, with broadly oblong to elliptic repand or undulate leaves, of the Southern States, perhaps extends northward into Missouri.
Prasium purpureum Walt. Fl. Car. 166. 1788?
Drac. denticulatum Ait. Hort. Kew. 2: 317. 1789.
P. virginiana var. denticulata A. Gray, Syn. Fl. 21: 383.
Stem slender, ascending or erect, simple, or little branched, 1°-2° high. Leaves firm or rather thin, oblong, linear-oblong, or oblanceolate, obtuse or acute at the apex, narrowed at the base, crenulate, obtusely dentate, or entire, 1'-3' long, 2"-6" wide, the upper sessile, the lower slender-petioled; spike loosely few-several-flowered; bracts lanceolate, little longer than the fruiting pedicels; flowering calyx oval-campanulate, its teeth acute, about one-third as long as the tube; fruiting calyx oblong, 3"-4" long; corolla rose-pink, nearly or quite 1' long.
In moist soil, Pennsylvania to Illinois, Florida and Texas. June-Aug.
Dracocephalum intermedium Nutt. Trans. Am. Phil.
Stem very slender, usually quite simple, 1°-3° high. Leaves usually few pairs, remote, thin, mostly shorter than the internodes, narrowly lanceolate or linear, acute or acuminate at the apex, repand-denticulate, little narrowed at the base, all sessile, or the lowest petioled, 2'-3' long, 2"- 4" wide; spikes very slender, remotely many-flowered, 4'- 8' long in fruit; lower bracts often nearly as long as the campanulate calyx; calyx-teeth acute, shorter than the tube; fruiting calyx broadly oval, 2"-2i" long; corolla much dilated above, 5"-7" long.
On prairies, western Kentucky to Missouri, Louisiana, Arkansas and Texas. May-July.
12: 434. As synonym. 1848. A. Gray, Proc. Am.
Acad. 8: 371. Not Dracocephalum parviflorum Nutt.
Stem rather stout, usually simple, 1°-3° high. Leaves lanceolate, oblong-lanceolate, or ovate-lanceolate, acute, acuminate, or the lower obtuse at the apex, sharply serrate or dentate, somewhat narrowed at the base, all sessile or the lowest petioled, thin, 3'-4' long, 3"-10" wide; spikes densely several-many-flowered, 1'-4' long; bracts ovate or ovate-lanceolate, acute, shorter than the calyx; flowering calyx campanulate, its teeth ovate, obtuse or subacute, about one-third as long as the tube; fruiting calyx globose-oblong, 2"-3' long; corolla purple, 5"-7" long.
In moist soil, Wisconsin and Minnesota to Nebraska, North Dakota, Saskatchewan, British Columbia and Oregon. June-Aug.