LABIAT.E. (mIXT FAMILY.) 325 



2. M. alba, n. sp. Smooth or hirsute ; leaves wedge-lanceolate or oblong, 

 toothed, rounded at the apex narrowed to the sessile base ; the lowest oblong, 

 tapering into a slender petiole ; the floral ones ovate or orbicular, obtuse ; whorls 

 4-flowered ; calyx nerveless, with the two larger lobes notched ; corolla white, 

 the upper lip emarginate. — Low pine barrens. West Florida, near the coast. 

 July and Aug. — Stem 1 ° - H° high. Leaves 2' long, or the radical ones 4' - 5' 

 long, and, like the calyx and corolla, thick and somewhat fleshy. 



22. PHYSOSTEGIA, Benth. 



Calyx tubular-bell-shaped, inflated in fruit, nearly equally 5-toothed. Corolla 

 tubular-funnel-shaped, 2-li])ped ; the upper lip erect, concave, entire or notched, 

 the lower spreading, broadly 3-lobed. Stamens 4, ascending under the upper 

 lip : anthers approximate, with the cells parallel, ciliate. Nutlets smooth, 

 acutely .3-angled. — Smooth perennial herbs, with erect mostly simple stems, 

 and opposite showy purplish flowers, in terminal spikes or racemes. 



I. P. Virginiana, Benth. Leaves large (6' -9' long), oblong, sharply 

 serrate, the lowest narrowed into a petiole ; spikes thick, dense-flowered ; calyx- 

 teeth acute ; corolla 1' long. (Dracocephalum Virginianum, L.) — Varies through 

 several intermediate forms, including Dracocephalum variegatum, Vent., and D. 

 obovatum. Ell., into var. denticulata, with lanceolate or linear denticulate or 

 entire leaves, and smaller (6"- 9" long) flowers in a long loosely flowered spike. 

 — Low ground and swamps, Florida to Mississippi, and northward. June- 

 Aug. — Stem 2° - 4° high. Racemes simple or compound. 



23. LAMIUM, L. Dead-Nettle. 



Calyx tubular-bell-shaped, 5-nerved, nearly equally .5-toothed, the teeth subu- 

 late, not spmy. •Corolla slender, dilated at the throat, 2-lipped ; the upper lip 

 ovate or oblong, narrowed at the base ; the lateral lobes small, at the margins of 

 the throat; the lowest lobe large, notched, contracted at the base into a short 

 stalk. Stamens 4, ascending under the upper lip : anther-cells at length spread- 

 ing. Nutlets 3-angled, truncate at the apex. — Herbs. Leaves incised ; the 

 lower ones petioled, the floral ones sessile, longer than the dense whorls. 



1. L. amplexicaule, L. Leaves orbicular, incisely crenate-lobed ; the 

 floral ones clasping, the others long-petioled ; tube of the corolla straight, the 

 lateral lobes truncate ; anthers hairy. — Cultivated ground and waste places, 

 common. May. ® — Stems 4'- 12' high Corolla small, purple, often im- 

 perfectly developed. 



24. MARRUBIUM, L. Horehound. 



Calyx tubular, 5-10-nerved, nearly equally 5- 10-toothed ; the teeth spiny, 

 mostly spreading in fruit. Corolla-tube included in the calyx, 2-lipped ; the 

 upper lip erect ; the lower 3-lobed, with the middle lobe largest. Stamens 4, 

 included : anther-cells diverging. Lobes of the style short, obtuse. Nutlets 

 obtuse at the apex. — Chiefly tomentose or woolly perennial herbs, with rugose 

 leaves, and axillary whorls. 

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