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giant trillium, sessile trillium

brook trillium, brook wakerobin

Leaves

ovate to broadly ovate, 6–20 × 5–15 cm, with weak mottling; spots often fading, not glossy;

apex rounded to obtuse, sessile.

1.7–11 cm × 0.8–6 cm, blue-green; glossy; leathery;

apex acute to acuminate;

base lanceolate to cordate;

petioles (0.5)1– 3(6) cm.

Scapes

1–3 (rarely more), 20

1–2, 4–20 cm, glabrous.

Flowers

sessile;

sepals lanceolate, 15–65 × 4–15 mm, green;

margins entire;

apex acute;

petals erect or slightly spreading, linear to obovate, 2–8 × 0.5–3 cm, white to cream-colored;

base sometimes rose pink to purple, rarely entire petal purple;

base often cuneate;

apex rounded to acute;

margins entire;

stamens erect, 10–25 mm;

filaments 1–4 mm, white to greenish white;

anthers erect, 10–20 mm, yellow or greenish white;

ovary ovoid, green or sometimes purple;

stigmas erect to spreading, 3–7 mm.

pedicel 2-10 cm;

sepals 3, green, lanceolate or ovate to oblong, 10–23 × 4–8(11)mm;

margins entire;

apex rounded to apiculate;

petals erect to spreading; ovate-cordate to orbicular, 1.3–2.8(3) × (0.8)1–2.4 cm, white, usually with dark purple spots;

base rounded to cuneate;

margins entire;

apex apiculate to acuminate;

veins inconspicuous or sometimes with pale venation;

stamens 6–15 mm; erect;

filaments white;

anthers straight, 3–6 mm, yellow;

ovary ovoid, 3–9 × 4 mm, white to cream, weakly 6-angled;

stigmas recurved, 2–4 mm, white to cream.

Fruits

ovoid to globose, green to maroon.

globose; greenish white.

55 cm long.

Trillium albidum

Trillium rivale

Distribution
[WildflowerSearch map]
[BONAP county map]
[WildflowerSearch map]
Discussion

2 subspecies.

The two subspecies of T. albidum are known to hybridize where their ranges overlap. This hybrid is sometimes referred to as T. × oregonum.

Stream banks, talus slopes, forest clearings, generally in serpentine soils. Flowering Mar–Jul. 50–1300m. CR, Sisk. CA. Native.

This species is sometimes placed in its own monotypic genus, Pseudotrillium.

Source Flora of Oregon, volume 1, page 314
Tamra Prior
Flora of Oregon, volume 1, page 316
Tamra Prior
Sibling taxa
T. cuneatum, T. kurabayashii, T. ovatum, T. petiolatum, T. rivale
T. albidum, T. cuneatum, T. kurabayashii, T. ovatum, T. petiolatum
Subordinate taxa
T. albidum ssp. albidum, T. albidum ssp. parviflorum
Synonyms Trillium chloropetalum Pseudotrillium rivale
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