prairie onion - Species Profile
Conservation • Description • Habitat • Ecology • Use • Distribution • Taxonomy
Conservation Status
IUCN Red List
not listed
NatureServe
NNR - Unranked
SNR - Unranked
Minnesota
not listed
Description
Prairie onion is an erect perennial forb rising from 2 to 5, sometimes more, clustered bulbs.
The bulbs are ⅔″ to 1⅛″ tall, ⅜″ to 1″ wide, and egg-shaped. They are encased in a brownish or grayish membranous coating. They gradually taper to the stem.
Three to five basal leaves arise near together at the soil surface forming a basal rosette. They are shorter than the stem. They are 4″ to 18″ long, about ⅛″ wide, linear, flat, stiff, and solid, with a small ridge running the length of the blade. They sheath the stem near the soil surface. They remain after the flowers are fully formed.
A single, leafless, flowering stem (scape) rises from the center of the rosette of leaves. When in bud, the scape bends downward (nods) at the top, and the umbel faces toward the ground. By the time the flowers are fully mature the scape is erect and the flowers face upward.
The inflorescence is a single umbrella-like flowering cluster at the top of the scape. The cluster is shaped like half of a sphere. It has 8 to 35 flowers and no bulblets. There are two bracts at the base of the cluster that soon fall off.
The flowers are ¼″ to ½″ wide and star-shaped. They are composed of 6 white to pink tepals (3 petals and 3 sepals that are similar in appearance). They are on ¼″ to ¾″ long flower stalks, the inner ones on shorter stalks, the outer ones on longer stalks, like an umbrella. There is no floral fragrance, but the bulb and foliage have an onion-like scent.
The fruit is a seed capsule. The pedicels become stouter with the fruit, growing longer and bending abruptly upright from near the point of attachment.
Height
1′ to 2′
Flower Color
White to pink
Similar Species
Meadow garlic (Allium canadense var. canadense) blooms much earlier, May to June. The scape never nods. It has 3 to 6 basally-sheathed leaves, attached only in the lower quarter or third of the stem. The leaves are flat and soft. Most or all of the flowers in the inflorescence have been replaced with bulblets. The flowers are bell-shaped.
Nodding wild onion (Allium cernuum var. cernuum) has tall, elongate, slender, and cone-shaped bulbs. The leaves are soft. The scape nods permanently, both when the flowers are in bud and when the flowers are fully open. The individual flowers of prairie onion are bell-shaped.
Textile onion (Allium textile) is a shorter plant, reacing only 4″ to 12″ at maturity. It blooms much earlier, May to June. It has only 1 or 2 basal leaves. The leaves are half-round, more or less straight, and solid, with a wide, rounded channel running the length of the blade. The scape never nods, and does not rise above the level of the leaves. The tepals are white, only rarely pink, and have red or reddish-brown midribs.
Habitat
Dry. Prairies, hillsides. Full sun.
Ecology
Flowering
July to September
Pests and Diseases
Use
Distribution
Nativity
Native
Occurrence
Common
Taxonomy
Kingdom
Subkingdom
Pteridobiotina
Phylum
Tracheophyta (Vascular Plants)
Class
Liliopsida (Monocots)
Order
Asparagales (Agaves, Orchids, Irises, and Allies)
Family
Amaryllidaceae (Amaryllis, Onions, and Allies)
Subfamily
Allioideae (Onion)
Tribe
Allieae
Genus
Allium (Onions)
Subgenus
Amerallium
Section
Lophioprason
Subordinate Taxa
Synonyms
Hexonychia stellatum
Stelmesus stellatus
Common Names
autumn onion
autumn wild onion
prairie onion
wild onion
