Common Horehound - Marrubium vulgare
Other Names:
White Horehound
Taprooted perennial. Stems ascending to erect, simple, 30–100 cm. Herbage white-wooly. Leaves cauline, short-petiolate; blades ovate, crenate, 1–3 cm long. Inflorescence of dense, head-like verticillasters in leaf axils. Flowers: calyx 4–6 mm long, wooly with long hairs within the throat, the 10 hooked-spinulose teeth shorter than the campanulate tube; corolla white, 5–7 mm long, bilabiate, the 2 lips ca. equal in length; stamens 4. Nutlets minutely reticulate (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).