Lamium amplexicaule L.
Family - Lamiaceae
Stems - From a taproot, multiple from base, ascending to erect, to +20cm tall, purplish basally, greenish above, 4-angled, hollow, scabrous from retrorse strigillose pubescence.
Leaves - Opposite, lowest leaves petiolate. Petioles to -2cm long, with a few pilose hairs and some retrorse strigillose pubescence. Blades typically +/-5-lobed, to +2cm long and broad, rotund to reniform, pubescent, with reddish margins. Margins crenate. Upper leaves reduced to bracts.
Inflorescence - Verticillasters in the apical 1/2 of the stem. Cymules with 4-5 flowers each. Clusters bracteate. Bracts sessile, 5-7-lobed, often purplish, pubescent.
Flowers - Corolla bilabiate, pale pink to purplish, to -2cm long. Corolla tube to 1.2cm long, pubescent externally and internally. Upper lip of corolla galeate, 4-5mm long and broad, pubescent externally. Lower lip saccate, with 2 small appendages at apex. Appendages 2-3mm long. Stamens 4, didynamous, adnate near base of lower lip, included under the galea. Filaments white, 4-5mm long, slightly pubescent near the base. Anthers purplish, -1mm long. Style 1.8cm long, white, glabrous. Stigma 2-lobed. Ovary 4-parted, light green, 1.7mm long, glabrous. Divisions of ovary shaped like pie-pieces when viewed from above. Nutlets brown, 2mm long, glabrous. Calyx sericeous externally, glabrous internally, accrescent, 5-toothed. Calyx tube to 2mm long in flower. Teeth 2.2mm long in flower, acute.
Flowering - February - November.
Habitat - Waste ground, lawns, cultivated fields, pastures, roadsides, railroads.
Origin - Native to Eurasia and Africa.
Other info. - This aggressive little plant has spread throughout Missouri and nearly all of North America. The plant is tolerant of sun or shade, heat or cold. In cultivated areas that get tilled regularly, the plant can form large seas of pink in the spring. The plant can grow from small pieces of its stem so chopping the plant only helps it spread. It also grows well from seed.
Photographs taken in Brown Summit, NC., 2-4-03, and at Rock Hill Park, Boone County, MO., 3-27-04.