Lamium amplexicaule is an annual or winter annual herb 10-40 cm tall, from a taproot, branched at base, several weak stems, bases often reclining (decumbent).
Leaves opposite, those of lower stem long-stalked, blade to 1.5 cm long and wide, rounded to kidney-shaped, surface puckered by impressed veins, margin coarsely round-toothed to lobed, leaves below flower clusters stalkless, clasping stem, usually shorter than flowers.
Flowers purplish to 1.8 cm, bilaterally symmetrical, tubular, 2-lipped, hairy outside, tube straight, upper lip to 0.5 cm, deeply hood-shaped, with purple hairs, calyx hairy to 0.8 cm long, ovary superior, some plants also produce small, permanently closed flowers (cleistogamous); blooming and fruiting Mar.- Nov. Pollinated by bees (Lovell 1918).
Fruit dry nutlets 0.2 cm.
Wetland status: UPL.
Frequency in NYC: Very infrequent.
Origin: Eurasia, N. Africa.
Habitat: Garden and field weed, especially in fertile soil.