LAB I AT AE. 215 



316. MARRUBIUM. 



Bitter-aromatic whitish-woolly perennials, branched at the 

 base; leaves wrinkled; flowers small, much crowded in axillary 

 whorls; calyx tubular, 5-10-nerved, nearly equally 10- toothed, 

 the teeth spiny-pointed; corolla 2-lipped, the upper lip erect, 

 notched; the lower spreading, 3-cleft, the middle lobe broadest; 

 stamens 4, short, included in the corolla-tube, the upper pair 

 longer. 



Marrubium vulgare L. Horehound. Stems tufted, erect, simple, about 

 30 cm. high, densely white woolly, especially below; leaves broadly ovate, 

 obtuse, coarsely crenate, thickish, rounded or cuneate at base, rough, woolly 

 beneath, 1-3 cm. long, on petioles nearly as long; flower clusters dense, axillary; 

 calyx-teeth 10, subulate, hooked at the apex, hardened in fruit; corolla white. 

 Abundantly introduced. 



317. DRACOCEPHALUM. 



Coarse herbs with blue flowers in dense bracteate terminal 

 clusters; calyx tubular, 15-nerved, 5-toothed; corolla 2-lipped, 

 the upper lip erect, emarginate, the lower 3-lobed; stamens 4, 

 anther-cells divergent; nutlets ovoid, smooth. 



Dracocephalum parviflorum Nutt. Stems stout, erect, 20-60 cm. high; 

 leaves ovate-lanceolate, incisely dentate, 3-8 cm. long, slender-petioled ; 

 inflorescence spike-like, the flowers densely crowded in whorls in the upper 

 axils; bracts oblong to ovate, cut-toothed, the teeth bristle-tipped; calyx 

 cylindric, puberulent, the upper tooth broadest, all acuminate; corolla pale 

 blue, slightly exceeding the calyx. Medical Lake, Henderson. 



318. PRUNELLA. Heal All. 



Low perennials ; flowers in terminal or axillary heads or spikes ; 

 calyx tubular-bell-shaped, about 10-nerved, 2-lipped, not gibbous 

 on the upper side, closed in fruit; upper lip broad and flat, 

 truncate, with 3 short teeth, the lower 2-cleft; corolla 2-lipped, 

 slightly contracted at the throat and dilated at the lower side 

 just beneath it; upper lip arched, erect, entire; the lower reflexed- 

 spreading, 3-cleft; stamens 4, ascending under the upper lip, the 

 lower pair longer. 



Prunella vulgaris lanceolata (Barton) Fernald. Glabrous or nearly so, erect 

 or ascending, 15-40 cm. high; leaves ovate-oblong or oblong-lanceolate, acute or 

 obtuse, rounded or cuneate at base, entire or crenate, 2-6 cm. long; petioles 

 slender, about half as long as the blades; spikes terminal, very dense, 2-5 cm. 

 long; bracts very broad, ovate or orbicular, cuspidate-acuminate, ciliate; calyx- 

 teeth somewhat ciliate; corolla violet, 8-12 mm. long, hardly twice as long 

 as the purplish calyx. Moist ground, not common. 



319. MICROMERIA. 



Low sweet-odorous plants; flowers small, in the axils of the 

 leaves; calyx oblong or tubular, about 10-nerved, terete, not 



