SKULLCAP 565 



tracheae and wood fibers have simple pores. There is a strong 

 development of sub-epidermal collenchyma, especially in the angles 

 of the stems and branches. A secondary development of the fibro- 

 vascular bundles occurs in the older stems of thymus. 



SCUTELLARIA. Skullcap. The dried herb of Scutellaria lateri- 

 flora (Fam. Labiatae), a perennial herbaceous plant growing in wet 

 places in the United States and Canada. The plant blooms from 

 July to September, when the herb should be collected. 



Description. Stem quadrangular, 1 to 4 mm. in diameter, vary- 

 ing in color from yellowish-green to purplish-red, mostly glabrous 

 below and hairy above. Leaves (Fig. 239) ovate, ovate-oblong, or 

 ovate-lanceolate, opposite, 1.5 to 8 cm. in length, 0.5 to 2.5 cm. in 

 breadth; summit acute or acuminate; base acute, rounded or sub- 

 cordate; margin coarsely serrate ; upper surface dark green, glabrous ; 

 under surface light green, nearly smooth, veins of the first order 

 diverging at an angle of 65, curving upward and anastomosing near 

 the margin; petiole 2 to 10 mm. in length. Flowers axillary and 

 solitary above or in 1-sided racemes; calyx campanulate, toothed, 

 about 2 mm. in length; corolla white or blue, about 6 mm. in length, 

 the limb 2-lipped ; stamens 4, didynamous, hairy, the anthers of the 

 upper pair with 2 pollen sacs, the lower with one; style unequally 

 2-cleft and ovary deeply 4-parted. Fruit (Fig. 239) consisting of 

 4 ellipsoidal, distinctly tuberculate, light brown nutlets about 1 mm. 

 in length, borne on an enlarged torus known as the gynobase, and 

 enclosed by the persistent bilabiate calyx, the upper part of which 

 becomes helmet-shaped after fertilization, whence the name " Skull- 

 cap "; odor slight; taste bitter. 



INNER STRUCTURE. See Fig. 239. 



Powder. Dark green; non-glandular hairs, 1- to 3-celled, 0.100 

 to 0.200 mm. in length, the walls with numerous slight centrifugal 

 projections, the basal cell being large, broadly cylindrical, and the 

 apical cell narrow and with a sharp, frequently recurved summit; 

 glandular hairs with a 1- to 2-celled stalk and large, glandular head, 

 composed of 6 or 8 cells divided by vertical walls, indistinct; pollen 

 grains nearly spheroidal or ellipsoidal, smooth and from 0.015 to 

 0.025 mm. in diameter; fragments of corolla colored light pink with 

 hydrated chloral solution; narrow tracheae with scalariform and 

 reticulate thickenings, or bordered pores; sclerenchymatous fibers 

 narrow, with walls from 0.004 to 0.005 mm. in thickness and marked 

 by simple pores; epidermal cells of stem and corolla with distinct 

 striations; the stomata broadly elliptical and with very small open- 

 ings. In Scutellaria canescens the non-glandular hairs are 3- to 



