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Montana Field Guide

Montana Field Guides

Chaffweed - Centunculus minimus
Other Names:  Anagallis minima, Lysimachia minima

Species of Concern
Native Species

Global Rank: G5
State Rank: S2
(see State Rank Reason below)
State Threat Score: No Known Threats

Agency Status


External Links

State Rank Reason (see State Rank above)
Known from scattered locations across the state, though it is rare to uncommon in Montana. May be susceptible to some adverse impacts from human-caused disturbance due to its preference for vernally moist habitats in valley loctions.
General Description
Chaffweed is a low, annual herb with prostrate or erect stems, 2-10 cm long, that root at the nodes. The alternate leaves, 5-10 mm long, are egg to spoon-shaped with entire margins. Foliage is glabrous. Solitary, inconspicuous flowers on short stalks occur in the leaf axils. Each flower has a deeply 4-lobed calyx, 2-3 mm long, and a small, pink, 4-lobed, tubular corolla, ca. 1 mm long, that withers on the maturing ovary. There are 4-5 stamens, and the fruit is a globose capsule that is ca. 2 mm long.

Flowering and fruiting June-September.

Diagnostic Characteristics
Glaux maritima is similar but has lower leaves that are opposite each other.

Species Range
Montana Range Range Descriptions


Range Comments
Europe, South America, and in North America irregularly from Nova Scotia to British Columbia and south to Florida, California, and Mexico (except for much of the Rocky Mountains and Great Basin).

Observations in Montana Natural Heritage Program Database
Number of Observations: 26

(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)

Vernally wet, sparsely vegetated soil around ponds and along rivers and streams in the valleys and on the plains.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see

Ecological Systems Associated with this Species

Threats or Limiting Factors
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Heidel, B.L., S.V. Cooper and C. Jean. 2000. Plant species of special concern and plant associations of Sheridan County, Montana. Report to U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena, Montana. 96 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 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.
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Citation for data on this website:
Chaffweed — Centunculus minimus.  Montana Field Guide.  .  Retrieved on , from