Description

Key Characters:

Growth Form: Annual or short-lived perennial herbs.

Stems: Stems 4–angled and furrowed, 5–15 dm long, puberulent to glabrate.

Roots:

Leaves: Leaves simple. Opposite. Blades variable, lower ones broadly ovate to deltate in outline, 5–11 cm long, 4–6.5 cm wide, deeply palmately lobed, upper leaves gradually reduced in size and with fewer and smaller lobes, those of the inflorescence linear, unlobed. Surfaces puberulent. Petioles 2–4 cm long. Stipules absent.

Flowers: Flowers 6 to numerous, sessile, in dense verticillasters, bracteoles linear, up to ca. 7 mm long, spinose. Calyx actinomorphic, turbinate, 4–5 mm long, enlarging to 6–7 mm long in fruit, glabrous to sparsely puberulent, the teeth subulate, splitting longitudinally usaully persistent or sometimes only ventral 1/2 persistent. Corolla zygomorphic, bilabiate, white, pink, or reddish, 10–15 mm long, puberulent, upper lobe obovate, pubescent on outer side; nectary disk symmetrical. Stamens 4, in 2 pairs, ascending the upper corolla lip, lower pair slightly longer; anthers sacs coherent; anthers dithecal, opening by longitudinal slits. Ovary superior, 2-carpellate, placentation basal-axile; ovules 1 per ovary lobe; style 1, cleft, the branches equal; stigmas 2.

Fruit: Nutlets 4; 1-seeded; brown; ellipsoid; ca. 2 mm long. Seeds with endosperm absent or scanty and oily.

Ploidy: 2n = 20

Habitat: Naturalized in relatively dry areas; especially pastures.

Elevation Range: 40–600 m.