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Montana Field Guide

Montana Field Guides

Western Trillium - Trillium ovatum

Native Species

Global Rank: G5
State Rank: S4S5

Agency Status
MNPS Threat Rank:
C-value: 6

External Links

General Description
Short-rhizomatous, fibrous-rooted, glabrous perennials. Stems erect, 10–40 cm, naked below. Leaves (bracts) 3, sessile, whorled at the stem tip, 3–13 cm long, broadly ovate, acuminate. Inflorescence a solitary, terminal flower; pedicel 15–60 mm long. Flower regular, star-shaped; sepals green, narrowly lanceolate, 15–35 mm long; petals white or pinkish, fading to pink or reddish, separate, 25–40 mm; stamens shorter than petals; anthers yellow; style 3-lobed. Fruit a broadly ovoid, 3-winged, many-seeded capsule, 12–25 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX; Hichcock and Cronquist 1973)

Species Range

Range Comments
AB south to CA, ID and CO (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 77

(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)


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Citation for data on this website:
Western Trillium — Trillium ovatum.  Montana Field Guide.  .  Retrieved on , from