Allium cernuum (Nodding onion)

Allium cernuum Roth

Nodding onion

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Liliopsida	Monocots (plants with a single seed leaf); includes the lily family
Subclass	Liliidae	Includes lilies, orchids, and many others
Order	Asparagales	A diverse group that includes asparagus
Family	Amaryllidaceae	Amaryllis family—plants that grow from bulbs. Includes onions and many others
Genus	Allium	Onions, leeks, shallots, garlic, scallions, etc.
Species	cernuum	Means "dry seed head"

About plant names...

Nodding onions have long narrow grass-like leaves about a foot in length and ¼" (6.3 mm) in width. A rosette of leaves at the base of the plant is vase-shaped. They lack the bulbs present in most other members of the onion family (onions are members of the lily family).

Identification: The most obvious feature of this plant is the one that gives it its common name—the flowerhead tilts or nods, a result of a small crook near the top of the stem.

Online References:

Allium cernuum on Vascular Plants of the Gila Wilderness

Allium cernuum at Illinois Wildflowers

Allium cernuum at the Oregon Flora Image Project

Allium cernuum on Plants for a Future, a resource and information centre for edible and otherwise useful plants

Allium cernuum at the Lady Bird Johnson Wildflower Center

Allium cernuum on Wikimedia Commons

Allium cernuum at the Missouri Botanical Garden

Allium cernuum on eFloras