Perennials, 5–35 cm; stolons present. Stems prostrate, rooting adventitiously, branched near base, glabrous. Leaves: petiole 0 mm; basal leaves: blade oblanceolate, 10–40 × 3–15 mm, faces glabrous; cauline leaves: blade obovate to spatulate, 8–30 × 4–12 mm, base long-cuneate, faces glabrous. Racemes scapose or terminating stolons, 5–15 cm. Pedicels 2–10 mm, glabrous; bracteoles narrowly triangular, 1.5–2 mm, glabrous. Flowers: calyx 4.5–7 mm, glabrous, tube 2.5–4 mm, lobes 2.5–4 mm; corolla 13–22 mm, tube 6–7.5 mm, abaxial lobes 7–13 mm, adaxial 6–8 mm. Capsules 3.5–5 × 3–3.5 mm. Seeds 0.4–0.6 × 0.3–0.4 mm. 2n = 20 (Asia).
Phenology: Flowering spring–late summer.
Habitat: Lawns, shady, moist areas.
Elevation: 10–500 m.
Introduced; Del., La., Md., Mich., N.J., N.Y., N.C., Pa., S.C., Tenn., Va., W.Va., e Asia, introduced also in Europe, Australia.
Mazus miquelii is often sold as M. reptans in the horticulture trade. Corollas of cultivated forms are sometimes solid white except for yellow spots in the throat; these may escape in the flora area.