Allium stellatum (Prairie Onion)
|Also known as:||Autumn Onion, Pink Wild Onion, Prairie Wild Onion|
|Habitat:||sun; dry fields, prairies, rocky areas|
|Bloom season:||July - August|
|Plant height:||8 to 18 inches|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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1½ to 2-inch round cluster of ¼-inch flowers, pale pink to deep pinkish purple, sometimes white, with a spot of yellow in the center and long yellow-tipped stamens. Individual flowers have 6 spreading tepals (3 petals and 3 sepals that look similar). At the base of the cluster are 2 or 3 papery bracts that persist through flowering. A plant has a single cluster at the end of a long naked stem. The cluster is sometimes initially nodding but the stem becomes erect as flowers develop.
Leaves and stem:
A few narrow grass-like blades, up to as long as the plant is tall, sheath the flowering stem near the soil line, appearing basal. Leaves and stems are hairless and have an onion smell to them. The underground bulbs are round to oval.
Prairie Onion is similar to the rare Nodding Wild Onion (Allium cernuum), which, as the name suggests, has flower clusters that hang down where Prairie Onion's are erect. While the bent flowering stalk of A. cernuum may be a key difference the distinction is not always so clear, as flowers of both species may initially nod. Other notable differences are: the tepals of A. stellatum flowers are more spreading than A. cernuum (but this can be subtle), the bracts at the base of the A. stellatum cluster persist through flowering, where they usually wither away in A. cernuum, and the underground bulbs of A. stellatum are ovoid and A. cernuum are elongated. Also, while A. stellatum may be found throughout much of Minnesota, A. cernuum is restricted to a few southeast counties, primarily on wooded, north facing slopes above creeks and rivers; A. stellatum habitat is drier and more open, sandy or rocky prairie.
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Photos by K. Chayka taken at Long Lake Regional Park, Ramsey County. Photos courtesy Peter M. Dziuk taken at Ordway Prairie, Pope County, in Anoka County, and a private garden in Ramsey County.
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