Vascular Plants of North Carolina
Account for Nodding Onion - Allium cernuum   Roth
Members of Allium with account distribution info or public map:
Google Images
Section 5 » Order Liliales » Family Alliaceae
Show/Hide Synonym
AuthorRoth
DistributionOnly in the Piedmont and mountains, and seemingly scarce in the western half of the Piedmont. Thus, it appears to have a bimodal range in the state -- low mountains and central and eastern Piedmont. It does not occur in the Coastal Plain.

The species has a very wide range, from the Atlantic to the north Pacific. In the east it ranges from ON and NY south only to northern SC, northern GA, and OK.
AbundanceInfrequent in the eastern and central Piedmont, but can be locally numerous in a few favored places. Very rare to rare in the western Piedmont, but uncommon to infrequent in the lower elevations of the mountains.
HabitatThis species favors, if not requires, dry to mesic and circumneutral soil of glades, open woods, barrens, meadows, edges of outcrops, and even grassy roadsides. It does well in full sun, as well as in light shade.
See also Habitat Account for Basic Barrens and Glades
PhenologyBlooms from June into early August; fruits from August to October.
IdentificationAs this is the primary species of onion in the state with a nodding inflorescence, it should be easily identified. In fact, plants at the middle and high elevations were formerly included with this species, but most or all are now split off as A. allegheniense. Allium cernuum has a flowering stem growing to about 1-1.5 feet tall, topped by an umbel that clearly is nodding, with the flowering pointing downward. There are a few basal leaves that are flat in cross-section and reach about 1 inch long but only 1/4-inch wide. The one or two dozen flowers are mainly pink in color, but can be white or rose (on different plants). The pedicels are about 1 inch long, and the tepals are barely 1/3-inch long, usually not fully spread. The quite similar A. allegheniense, a recent split, has purple to magenta flowers, the flowers are usually more urn-shaped (rounded) with a small opening, and grows mainly above 3500 feet in elevation. Nodding Onion is a good indicator species of circumneutral soils, and often a number of rare "prairie plants" can be found with it. Many of the state's noteworthy Piedmont barrens and glades contain this species.
Taxonomic CommentsMany or most references do not yet recognize A. allegheniense, and thus those would consider A. cernuum to be more widespread or numerous in the mountains. Weakley (2018) suggests that the extensive but fragmented global range may indicate that more than one cryptic species is involved.

Other Common Name(s)Lady's Leek
State RankS4
Global RankG5
State Status
US Status
County Map - click on a county to view source of record.
Select a source
AllHerbaria
Individual
Website
Select an occurrence type
AllCollection_naturalSight_natural