Marrubium vulgare L.
horehound
Much-branched herb with stems to c. 50 cm tall, ± lanate. Petioles slender, < to > lamina, lanate or densely hairy. Lamina 1-3.5 × 1-4.5 cm, broad-ovate to suborbicular, rugose, white-tomentose except for upper surface when mature, crenate or crenate-dentate; base truncate to cuneate in upper lvs and bracts, subcordate in lower lvs; apex obtuse. Verticels dense, globose. Calyx tube 4-6 mm long, with stellate tomentum; teeth 10, rigid, subulate, hooked. Corolla c. 1 cm long, white-tomentose outside; lower lip broader than long. Nutlets c. 2.5 mm long, ± obovoid, sharply keeled.
N.; S.: abundant in drier areas, particularly in Canterbury and Otago, much less common north of the Volcanic Plateau; Ch.
Eurasia, N. Africa 1867
Open, dry pastures, rocky ground and disturbed sites such as roadsides, railways, heaps of spoil, waste places.
FL Nov-Mar.
Horehound has long been valued as a medicinal plant in its homelands and was therefore probably introduced deliberately to N.Z. It is rarely cultivated here now.
