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Montana Field Guides

Whorled Milkwort - Polygala verticillata

Native Species

Global Rank: G5
State Rank: S3S4
(see State Rank Reason below)
C-value: 4

Agency Status


External Links

State Rank Reason (see State Rank above)
Polygala verticillate is fairly common in portions of eastern Montana. Plants grow in habitats that are widespread and relatively secure. Threats or factors that limit populations have not been identified. Current data on population sizes, locations, and threats to habitats are needed.
  • Details on Status Ranking and Review
    Whorled Milkwort (Polygala verticillata) Conservation Status Review
    Review Date = 08/25/2020
    View State Conservation Rank Criteria
    Range Extent

    ScoreF - 20,000-200,000 sq km (~8,000-80,000 sq mi)

    Comment64,487 square kilometers.

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    CommentMontana can be divided into 30,390 4x4 square kilometer cells. For this species plant observations occur in 22 of these 4x4 square kilometer cells.

    Number of Populations

    ScoreC - 21 - 80

    Comment30 observations.

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce

General Description
PLANTS: Annual plants that grow from a taproot. Stems are erect but branched, without hairs (glabrous), and 5–20 cm tall. Source: Lesica et al. 2012

LEAVES: Arranged in whorls or alternately on the stem. Leaf blades are simple with entire margin, linear to linear-oblanceolate in shape, without stipules, and 1–2 cm long. Source: Lesica et al. 2012

INFLORESCENCE: Spike-like racemes that come from the axils of the leaves. Flowers are white to pink with male and female organs (perfect), irregular, and hypogynous. Sepals are 5 of which 2 are large and petal like while 3 are small. Petals are 3 and united below. Wing petals are 1–2 mm long. Lower petal is keel-shaped, 1–1.5 mm long with 1 to 2 lobes on each side. Stamens: 8. Ovary with a 2-lobed style. Fruit is a capsule. Source: Lesica et al. 2012

Diagnostic Characteristics
The flowers of Polygala can resemble papilionaceous flowers which are characteristic for members of the Pea (Fabaceae) Family. Montana has 2 Polygala species:

Whorled Milkwort - Polygala verticillata, native and desirable
*Life Form: Annual with a taproot.
*Leaves: Lower ones are whorled.

White Milkwort - Polygala alba, native and desirable
*Life Form: Perennial with a branched caudex.
*Leaves: Lower ones are alternate.

Species Range
Montana Range Range Descriptions


Range Comments
Manitoba in Canada to Massachusetts south to Utah, Texas, and Florida in the U.S. (Lesica et al. 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 28

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

In grasslands in the plains zone of Montana (Lesica et al. 2012).

Reproductive Characteristics
Plants reproduce by seed.

Capsule: ellipsoid, 2-celled (locules), and about 2 mm long (Lesica et al. 2012). Seeds: 1 per cell and enclosed in an aril.

  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • DuBois, K.L. 1979. An inventory of the avifauna in the Long Pines of Southeastern Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 113 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Seipel, T.F. 2006. Plant species diversity in the sagebrush steppe of Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 87 p.
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Citation for data on this website:
Whorled Milkwort — Polygala verticillata.  Montana Field Guide.  .  Retrieved on , from