25. Allium rotundum Linnaeus, Sp. Pl., ed. 2. 1: 423. 1762.
Bulbs 1–50+, ovoid, 0.2–1.5 × 0.2–1 cm; outer coats surrounding numerous, very dark purple bulbels, usually white or greenish, membranous, sometimes breaking into ± parallel, fibrous strips; inner coats white, cells obscure, quadrate. Leaves persistent, 2–5, sheathing 1/3–1/2 scape; blade solid, flat or channeled, carinate, 15–40 cm × 2–5(–7) mm, margins entire. Scape persistent, solitary, erect, ± solid, 25–90 cm × 1–4 mm. Umbel persistent, erect, very dense, 80–200-flowered, globose, bulbils unknown; spathe bracts caducous, 2, 7–12-veined, lanceolate, ± equal, apex narrowed to beak, beak to 2 cm. Flowers campanulate, 4–7 mm; tepals erect, purple, or inner with broad whitish margins and purple midvein, oblong to ovate, ± equal, becoming keeled and ± rigid in fruit, margins entire, apex acute to obtuse; stamens included; filaments: outer unlobed, inner with 2 prominent teeth on either side of anther, teeth 2–3 times anther-bearing portion, usually papillose to ciliate; anthers yellow or purple; pollen light yellow to white; ovary crestless; style linear, ± equaling anther-bearing portion of stamens; stigma capitate, unlobed; pedicels 5–30 mm, outer much shorter than inner. Seed coat dull; cells each with central papilla.
Flowering May--Jul. Disturbed fields and roadsides; introduced; Mich.; c, s Europe.
Allium rotundum is native to central and southern Europe. It is reported as established in southern Michigan, and is to be expected elsewhere in the Great Lakes region.