Allium fistulosum L.
Family: Amaryllidaceae
Welsh Onion
Allium fistulosum image
Tracey Slotta  
Bulbs 2-12+, borne on short rhizome, cylindric, 2-5 × 1-2.5 cm; outer coats enclosing 1 or more bulbs, white to light brown, membranous, without reticulation; inner coats white, cells obscure, quadrate. Leaves persistent, 2-6, sheathing lower 1/4-1/3 of scape; blade terete, fistulose, 10-40 cm × 10-25 mm. Scape persistent, solitary, erect, fistulose, inflated in middle, tapering to umbel, (12-)15-70 cm × 8-25 mm. Umbel persistent, erect, compact, 50-100-flowered, globose to ovoid, bulbils unknown; spathe bracts persistent, 1-2, 1-3-veined, ovate, ± equal, apex acute. Flowers narrowly campanulate to urceolate, 6-9 mm; tepals erect, yellowish white, withering in fruit, margins entire, apex acute, outer lanceolate, inner narrowly ovate, unequal; stamens long-exserted; anthers white to yellow; pollen white; ovary crestless; style linear, equaling stamens; stigma capitate, obscurely 3-lobed; pedicel 10-30 mm. Seed coat shining; cells 4-6-angled, ± rectangular. Flowering Jul--Aug. Disturbed areas; introduced; N.W.T.; Alaska; cultivated in Europe, Asia. Allium fistulosum is cultivated in Europe and Asia. It is reported to have escaped in Alaska and is established near the north end of Great Slave Lake. The species is to be expected elsewhere in Canada and the northern United States.

Perennial herb with two to twelve or more bulbs flowering stem 12 cm - 0.7 m tall, inflated in the middle Leaves: two to six, arising near the base, 10 - 40 cm long, 1 - 1.5 cm wide (sometimes wider near the base), cylindrical with a long-pointed tip, hollow. Inflorescence: an upright, rounded, compact umbel of 50 to 100 flowers raised on a single hollow stalk and subtended by one to two persistent bracts. Flowers: on stalks shorter or equal to flowers, yellowish white, 6 - 9 mm long, narrowly bell-shaped, with six tepals that wither in fruit. Stamens six, long-exserted. Anthers white to yellowish. Fruit: a short, three-lobed capsule. Bulbs: up to 5 cm tall, more than twice as long as wide, cylindrical, and encased in a white to light brown membranous coating.

Similar species: The cylindrical, hollow leaves and inflated stems of this species and Allium cepa help distinguish them from other Allium found in the Chicago Region. Allium cepa differs from A. fistulosum by having flower stalks that are much longer than the flowers.

Flowering: May to August

Habitat and ecology: Introduced from Asia. Rare in the Chicago Region. There is a single record from Lake County, Illinois, where it was found growing in a roadside ditch.

Occurence in the Chicago region: non-native

Notes: Reported to have escaped and become established in Alaska.

Etymology: Allium comes from the Latin word for garlic. Fistulosum means hollow or tube-like.

Author: The Morton Arboretum