PLANT: annual; hairs non glandular; stems 4 45 cm tall. LEAVES: petioles 10 35 mm long; blades 5 18 mm long, 5 20 mm wide, mostly triangular-ovate, rarely longer than wide; bases mostly cordate; margins coarsely and irregularly crenate or serrate, rarely lobed. INFLORESCENCE: bracts ascending to horizontal, sessile or the lowest with a short petiole, 6 30 mm long, 8 40 mm wide, reniform to broadly ovate, the base truncate to somewhat clasping, the margin shallowly lobed and coarsely and irregularly crenate. FLOWERS: calyx 4 7 mm long, pilose; corolla red purple, 10 20 mm long, the hood with red purple trichomes dorsally, the lower lip white with red purple margin and spots with middle lobe contracted near base. NUTLETS: ca. 2 mm long, shiny brown with white patches. 2n = 18, 36. NOTES: Lawns, roadsides, riparian and disturbed areas: to be expected in most populated areas of AZ but specimens only document Cochise, Coconino, Gila, Greenlee, Maricopa, Pima, Pinal, Santa Cruz, Yavapai cos.; 350 2150 m (1100 7000 ft); Feb May; extensively naturalized in the New World, including nearly all of the continental U.S.; Eur. This species is easily recognized by its long exserted flowers and the broad, overlapping, sessile bracts that form a platform or bowl below each of the widely spaced verticils. The other widely naturalized species of this genus, L. purpureum L., occurs in most of the states bordering AZ. It can be easily distinguished by its petiolate, reflexed bracts which usually overlap the bracts of the subjacent verticil. REFERENCES: Christy, Charlotte M. 2003. Lamiaceae J. Ariz. - Nev. Acad. Sci. Volume 35(2).
Annual 1-4 dm from a short taproot, generally branched at the base, the several weak stems decumbent below; herbage inconspicuously hairy or subglabrous; proper lvs restricted to the lower part of the stem, petiolate, with broad, rounded, ±cordate, coarsely crenate or lobulate blade seldom 1.5(-2) cm; lvs subtending the fl-clusters sessile, broad-based, clasping, often 1.5(-2.5) cm, surpassing the cals but usually surpassed by the cors; verticils few and (except sometimes the upper) mostly well spaced, the lowest fully developed one often borne at or below the middle of the stem; lowest verticil sometimes few-fld and subtended by petiolate lvs; cal hirsute, 5-8 mm, the narrow,
erect lobes about equaling the tube; cor purplish, 12-18 mm, glabrous inside, hairy outside, the tube straight; upper lip 3-5 mm, with purple hairs; occasional plants produce small, cleistogamous fls; 2n=18. A weed in fields and waste places, especially in fertile soil; native to Eurasia and n. Africa, now well established in our range and elsewhere in Amer. Mar.-Nov.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Duration: Annual Nativity: Non-Native Lifeform: Forb/Herb General: Annual or biennial with sparsely pubescent herbage and decumbent to ascending stems 5-35 cm long, branching at base and from some axils. Leaves: Broadly ovate to suborbicular, truncate to cordate at base, obtuse to rounded at apex, coarsely crenate, dark green above, slightly paler beneath, lower leaves 5-10 mm wide, slenderly petiolate, upper sessile and often clasping, 20-25 mm wide, nearly as long. Flowers: Cymules few-flowered; calyx hispidulous 4-5 mm long, teeth equaling or slightly longer than broad tube, corolla purple to lavender, 10-16 mm long, tube slender, sparsely hirsute below, becoming densely pubescent upward, upper lip bearded with lavender to purplish hairs, lower lip with very small lateral lobes, middle lobe spotted with white and deep purple. Fruits: Nutlets obovoid-oblong, round back, trigonous in cross section, narrowly grooved down ventral midline, pale brown with paler numerous tubercles. Ecology: Found in waste places, disturbed areas, cultivated fields and lawns, very widespread. Flowers March-October. Notes: Widespread weed, naturalized extensively in United States, from Eurasia. Ethnobotany: Unknown Etymology: Lamium is the ancient Latin name for the mints, while amplexicaule refers to the leaf base clasping the stem. Synonyms: Lamium amplexicaule var. album Editor: SBuckley, 2010