Trillium ovatum Pursh
western trillium (Pacific trillium)
Melanthiaceae
(Previously in Liliaceae)

Introduction to Vascular Plants

Photograph

© David Blevins     (Photo ID #392)

Map

E-Flora BC Static Map

Distribution of Trillium ovatum
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SUBTAXA PRESENT IN BC

Trillium ovatum var. ovatum

Species Information

General:
Perennial herb from a short, stout, fleshy rhizome; flowering stems erect, 10-45 cm tall, unbranched, smooth throughout.
Leaves:
Stem leaves usually 3 in a whorl, 5-18 cm long, often as wide, broadly egg-diamond-shaped to triangular egg-shaped, smooth, unstalked or nearly so, the margins entire; basal leaves lacking.
Flowers:
Inflorescence a solitary, terminal, stalked flower, the stalk 1-8 cm long; flowers star-shaped, erect to nodding; petals 3, white turning pale pink to purple with age, sometimes pinkish initially, egg-shaped, 3-6 cm long; sepals 3, green and leaf-like, lanceolate to oblong, somewhat shorter than petals; stamens 6; pistil 1, 3-chambered.
Fruits:
Capsules, berry-like, green to yellowish, broadly egg-shaped, with wing-like ridges; seeds numerous, large, egg-shaped, in a sticky mass when first shed.
Notes:
Two varieties occur in BC:

1. Plants 20-45 cm tall; flowers opening white; the common variety........................ var. ovatum

1. Plants 10-20 cm tall; flowers opening pink; rare on western Vancouver Island..................... var. hibbersonii (Taylor & Szczawinski) Douglas & Pojar

Source:  The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Trillium ovatum

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
 Value / Class

Avg

Min

Max
Elevation (metres)
 670 5 1816
Slope Gradient (%)
 18 0 95

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

 315 0 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric] 		4 0 7
Modal Nutrient Regime
Class
 D
# of field plots
 species was recorded in:
 974
Modal BEC Zone Class
 CWH

All BEC Zones (# of stations/zone) species was recorded in

 CDF(139), CWH(467), ESSF(82), ICH(197), IDF(20), MH(1), MS(33), PP(2)

Habitat and Range

Moist forests in the lowland, steppe and montane zones (var. ovatum), and mossy bluff ledges and river boulders in the lowland zone (var. hibbersonii); common in S BC, south of 50degreeN; E to SW AB and S to CO and CA.

Source:  The Illustrated Flora of British Columbia

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