Swamp Onion

Allium madidum is found in the Blue Mountains, Oregon and in Idaho near Payette Lake and New Meadows.

Bulbs 1–3, larger bulbs each usually with cluster of 10–30 easily detached bulbels to one side of base, not clustered on stout, primary rhizome, globose to ovoid, 1–1.6 × 0.8–1.5 cm; outer coats enclosing 1 or more bulbs, brownish, membranous, without fibers; inner coats white to pink; inner and outer coats frequently without obvious reticulations, these, when present, contorted. Leaves persistent, green at anthesis, 2, basally sheathing, sheaths not extending much above soil surface; blade solid, flat or channeled, 10–25 cm × 1–4 mm, margins entire. Scape persistent, solitary, erect, solid, ± terete, sometimes ridged, 10–20 cm × 1–2 mm. Umbel persistent, erect, compact, 10–20-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2, 5–7-veined, ovate, ± equal, apex acuminate. Flowers campanulate, 6–10 mm; tepals erect or ± spreading, white with prominent green or pink midveins, lanceolate, ± equal, becoming papery in fruit, margins entire, apex obtuse to acuminate, becoming involute at tip; stamens included; anthers white or yellow; pollen yellow; ovary crestless or obscurely crested; processes 3, low, central, rounded, minute; style linear, equaling stamens; stigma capitate, unlobed or slightly lobed; pedicel 5–12 mm. Seed coat dull; cells ± smooth. 2n = 28, 42.

Idaho, Oreg.

Flowering May--Jul.

Seasonally wet meadows; 1100--2000m.