- To +20cm tall, decumbent at base to erect, multiple from fibrous roots, herbaceous, hollow, 4-angled, minutely retrorse strigillose on angles.
- Opposite, decussate, petiolate. Lowest leaves with petioles to +/-3cm long. Petioles ciliate. Blades cordate to reniform, crenate-serrate, pubescent. Upper leaves becoming triangular and acute, to 3cm long and broad.
- Dense verticillasters near the apex of the stems. Cymules typically 3-flowered. Leaves (bracts) subtended verticillasters typically with a dark purple stripe. Flowers sessile.
- Corolla bilabiate, to 1.5cm long, expanded near apex, glabrous internally. Contracted portion of tube typically +/-5mm long, glabrous. Upper lip galeate, pinkish externally, villous externally, 5mm long, 3-4mm broad. Lower lip from expanded portion of tube. Lateral lobes minute, 1mm long, linear-subulate, pink. Central lobe obcordate, reflexed, 2-3mm long, pink with darker spots at base. Stamens 4, didynamous, adnate near middle of corolla tube, included under galea. Filaments white, to 6mm long, glabrous. Anthers brownish, +1mm long, with some white floccose pubescence. Ovary 4-lobed. Lobes truncate at apex, wedge shaped in cross section and trigonous, glabrous, olive-green, .5mm long. Calyx tube 3mm long, 5-toothed, mostly glabrous, whitish-green with purple ribs. Teeth attenuate, ciliate and glandular pubescent, 3mm long. Calyx accrescent. Nutlets to +2mm long, glabrous.
- April - October.
- Waste ground, thickets, roadsides, railroads.
- Native to Eurasia.
- Although this may be an attractive little plant to look at, it should not be willingly spread as it is very invasive. This plant is becoming common throughout Missouri and is seen in its best condition during the months of April and May. If left undisturbed, the plant can form large colonies.
Photographs taken in Brown Summit, NC., 4-6-03.