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Montana Field Guide

Montana Field Guides

Marsh Felwort - Lomatogonium rotatum

Species of Concern
Native Species

Global Rank: G5
State Rank: S1S2
(see State Rank Reason below)
State Threat Score: Unknown
C-value: 6

Agency Status
USFS: Sensitive - Suspected in Forests (BRT)


External Links

State Rank Reason (see State Rank above)
Only two known occurrences in Montana on BLM and private lands, including one moderate-sized population. Livestock grazing occurs in the occupied habitat, though it is unclear what effect it may have on L. rotatum. Changes in the hydrology, particularly lowering of the water table may adversely affect populations.
General Description
Felwort is a glabrous annual with usually unbranched stems that are 5-15 cm high. The opposite leaves are narrowly oblong to lance-shaped and 1-3 cm long. White or bluish flowers are borne on slender, 1-3 cm long stalks which arise from the axils of the upper leaves. The 5 spreading, lance-shaped petals are 6-15 mm long and are united at the base and subtended by slightly longer, narrow, green sepals. Each petal has 2 small appendages at the base, and there are 5 stamens. The fruit is a many-seeded, egg-shaped capsule that is as long as the petals.

Flowering in August.

Diagnostic Characteristics
Swertia perennis has similar flowers but is a perennial. Annual gentians have tubular rather than star-shaped corollas. This plant is often overlooked because it blooms in August.

Species Range
Montana Range Range Descriptions


Range Comments
Greenland to Alaska, south to Colorado.

Observations in Montana Natural Heritage Program Database
Number of Observations: 4

(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)

Alkaline meadows and fens in the montane zone.
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

  • Additional ReferencesLegend:   View Online Publication
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    • Famous, N. C. and C. S. Campbell. 1984. Lomatogonium rotatum (Gentianaceae) and Primula laurentiana (Primulaceae) in Maine: New locations and general distribution. In prep.
    • Famous, N. C., and C. S. Campbell. 1985. Lomatogonium rotatum. In: The Nature Conservancy Element Stewardship Abstract [Data base]. Boston, MA: The Nature Conservancy, Eastern Regional Office.
    • 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.
    • Lesica, P., P. Husby, and S. V. Cooper. 1998. Noteworthy collections: Montana. Madrono 45:328-330.
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Citation for data on this website:
Marsh Felwort — Lomatogonium rotatum.  Montana Field Guide.  .  Retrieved on , from