1. Alliaria petiolata (Bieberstein) Cavara & Grande, Bull. Orto Bot. Regia Univ. Napoli 3: 418. 1913; Arabis petiolata Bieberstein, Fl. Taur.-Cauc. 2: 126. 1808. TYPE: “Hab. in Iberia,” D. Steuen s.n. (holotype, LE).
Erysimum alliaria Linnaeus, Sp. Pl. 2: 660. 1753; Sisymbrium alliaria (Linnaeus) Scopoli, Fl. Carniol., ed. 2, 2: 26. 1772; Alliaria officinalis Andrzejowski ex Bieberstein, Fl. Taur.-Cauc. 3: 445. 1819; A. alliaria (Linnaeus) Huth, Helios 11: 132. 1893. TYPE: “Habitat in Europae sepibus, cutis umbrosis.” (lectotype designated by Hedge (Taxon 51: 533. 2002), BM; see http//www.nhm.ac.uk/botany/databases/clifford/).
Sisymbrium alliaceum Salisbury, Prodr. 270. 1796; Alliaria alliacea (Salisbury) Britten ex Rendle, List Brit. Seed Pl. Ferns 3. 1907. nom. illeg.
Herbs biennial, with garlicy smell when crushed. Stems erect, (15-)30-90(-130) cm tall, simple or branched above, glabrous or pilsoe basally with trichomes to 1.5 mm. Basal leaves rosulate, withered by fruiting; petiole 3-10(-16) cm; leaf blade reniform to cordate, (0.6-)1.5-5(-7) cm wide, shorter in length, base cordate, margin crenate to dentate, glabrous or pilose. Cauline leaves with much shorter petioles, ovate, cordate, deltoid, to 15 ´ 15 cm, base cordate to truncate, margin acutely to obtusely toothed, apex acute. Racemes ebracteate or rarely lowermost flowers bracteate. Sepals oblong, (2-)2.5-3.5(-4.5) ´ 0.7-1.5 mm. Petals white, oblanceolate, (2.5-)4-8(-9) ´ (1.5-)2-3(-3.5) mm, attenuate to clawlike base. Filaments 2-3.5(-4.5) mm; anthers oblong, 0.7-1 mm. Fruiting pedicels divaricate to ascending, (2-)3-10(-15) mm, nearly as thick as fruit. Fruits linear, (2-)3-7(-8) cm ´ 1.2-2.5 mm, subtorulose, quadrangular to subterete, divaricate-ascending; valves glabrous, with a prominent midvein and 2 conspicuous lateral veins. Style (0.2-)1-2(-3) mm. Seeds brown to black, narrowly oblong, 2-4.5 ´ 0.7-2 mm, longitudinally striate. 2n = 42.
Flowering: Mar-Jun.
Habitat: waste places, roadsides, fields, woodlands, riversbanks.
Distribution: native of Europe and W Asia; introduced and naturalized in North America.