HOREHOUND 567 



nearly all of which have the flowers in terminal panicled racemes. 

 Heart-leaved skullcap (Scutellaria cordifolia) is densely glandular 

 pubescent, even the corolla being hairy; Hairy skullcap (S. pilosa) 

 is pubescent below, with numerous glandular hairs above, and the 

 corolla is nearly glabrous; Hyssop skullcap (S. integrifolia) has linear 

 entire upper leaves; in Marsh skullcap (S. galericulata) the flowers 

 occur in the axils of the nearly sessile, narrow leaves. The Euro- 

 pean skullcap (S. altissima) has broad, ovate, glabrous leaves and 

 terminal panicles of blue flowers. 



Substitutes. Scutellaria canescens, a plant growing west of the 

 Mississippi, furnishes much of the drug on the market. The plant 

 is more robust than S. lateriflora; the leaves are oblong, petiolate, 

 10 to 12 cm. in length, 3 to 5 cm. in breadth, very hairy on the under 

 surface, with prominent veins, and crenate-dentate margins; and 

 the flowers are large, blue and in terminal racemes (Fig. 239). 



Literature. Holm, Merck's Report, 1911, p. 247. 



MARRUBIUM. White Horehound. The leaves and flowering 

 tops of Marrubium vulgare (Fam. Labiatse), a perennial herb indig- 

 enous to Europe and Asia, and cultivated in various parts of Europe 

 and the United States, being naturalized in waste places from Texas 

 and Mexico to Maine and Ontario. 



Description. Stem quadrangular, yellowish- or grayish-green, 

 3 to 5 mm. in diameter, very pubescent; internodes 2 to 5 cm. in 

 length. Leaves broadly ovate, opposite, 1.5 to 6 cm. in length, 

 8 to 25 mm. in breadth; summit obtuse; base acute or rounded; 

 margin coarsely crenate; upper surface dark green, pubescent, veins 

 depressed, those of the first order diverging at an angle of about 65 

 and branching near the margin; under surface grayish-green, very 

 pubescent, veins prominent; petiole 0.5 to 3 cm. in length, very 

 pubescent. Flowers sessile, in axillary clusters; calyx tubular, 

 about 5 mm. in length, 5- to 10-nerved, very pubescent and with 10 

 recurved, bristle-like lobes; corolla whitish or light brown, about 

 7 mm. in length, upper lip erect, entire or bifid, lower lip 3-lobed, the 

 middle lobe the largest and emarginate; stamens four, included. 

 Nutlets brownish-black, ellipsoidal, slightly compressed, about 1.5 

 mm. in length, nearly smooth. Odor slight aromatic. Taste 

 aromatic and bitter. 



Inner Structure. Non-glandular hairs of 3 types,, (a) short, 

 unicellular hairs; (6) long-pointed, unicellular hairs, having papillose 

 walls; and (c) branched or tufted, multicellular hairs, having from 

 6 to 15 cells radiating from a central stalk. Glandular hairs of 2 

 types having either a short, or long stalk, and a 2- to 8-celled gland- 



