Allium cernuum, known as nodding onion or lady's leek, is a perennial plant in the genus Allium. It grows in dry woods, rock outcroppings, and prairies. It has been reported from much of the United States, Canada and Mexico including in the Appalachian Mountains from Alabama to New York State, the Great Lakes Region, the Ohio and Tennessee River Valleys, the Ozarks of Arkansas and Missouri, and the Rocky and Cascade Mountains of the West, from Mexico to Washington. It has not been reported from California, Nevada, Florida, Louisiana, Mississippi, New Jersey, Delaware, New England, or much of the Great Plains. In Canada, it grows from Ontario to British Columbia.<ref name="flora">Template:EFloras</ref><ref>Template:BONAP</ref><ref>Template:PLANTS</ref><ref>Template:Cite book</ref><ref>CONABIO. 2009. Catálogo taxonómico de especies de México. 1. In Capital Nat. México. CONABIO, Mexico City.</ref>
Allium cernuum has an unsheathed slender conical bulb which gradually tapers directly into several keeled grass-like leaves (Template:Cvt wide). Each mature bulb bears a single flowering stem, which terminates in a downward nodding umbel of white or rose flowers. Flowers appear in July or August. They are bell-shaped, about Template:Cvt across, pink or white with yellow pollen and yellow anthers. This plant does not have bulblets in the inflorescence.
The flowers mature into spherical crested fruits which later split open to reveal the dark shiny seeds.<ref name="flora" /><ref>Template:Illinois Wildflowers</ref><ref>Template:Cite journal</ref><ref>Template:Cite book</ref><ref>Template:Cite encyclopedia</ref><ref>Template:Cite encyclopedia</ref><ref>Template:Cite book</ref><ref>Template:Cite book</ref>