Ma Bian Cao

Verbena officinalis, common vervain, is a slender, erect perennial herb in the family Verbenaceae, native to Europe, the Mediterranean basin, and temperate Asia and naturalized across much of North America, South America, Australia, and Africa, where it grows along roadsides, in waste ground, dry meadows, and disturbed soils. The plant rises 30-100 cm from a woody rootstock on stiff, square, four-angled stems that are sparingly branched and roughly hairy on the angles. The opposite leaves are highly variable, the lower ones obovate to ovate and coarsely lobed or pinnately divided, the upper ones smaller, lanceolate, and toothed, all somewhat rough to the touch. Slender, elongated, terminal spike-like inflorescences bear small, pale lilac to whitish, five-lobed tubular flowers about 4 mm across that open a few at a time progressively up the spike from summer to autumn. The fruit is a dry schizocarp splitting into four nutlets.