The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links
Trillium ovatum

Pacific trillium, trillium, western trillium, western wake-robin, western white trillium, white or western trillium, white trillium

Idaho trillium, long-petioled trillium, petioled wakerobin, purple trillium, purple wakerobin, round-leaf trillium

Rhizomes

semierect to horizontal, short, stout, praemorse.

± erect, often very deep, praemorse.

Scapes

1–2, round, 2–5 dm, ± slender, glabrous.

typically 1, vertical but mostly subterranean, round in cross section, 0.4–1.7 dm, robust, glabrous.

Bracts

sessile, subsessile, or short-petiolate;

blade medium green, sometimes blotched and mottled, main veins prominent, ovate-rhombic, 7–12 × 5–20 cm, continuing to expand during anthesis, base rounded, apex acuminate.

just at or slightly above soil, long-petiolate;

blade medium green, not mottled, ovate to elliptic, 7–14 × 5.5–10.2 cm, not glossy, apex obtuse or rounded;

petiole arising from scape apex at or near ground surface, 5–12 cm;

bract and petiole strongly resembling leaves of Plantago.

Flower

erect or nodding, odorless;

sepals spreading to horizontal, green, lanceolate to oblong-lanceolate, 15–50 × 6–20 mm, margins entire, apex acute;

petals erect-ascending, usually wide-spreading from base, exposing entire pistil, white or with pink or blush markings, lacking V-shaped markings, fading to rosy pink, purple, or dark red, veins not deeply engraved, ± linear to widely obovate, 1.5–7 ×1–4 cm, widest at or above middle, thin-textured, margins flat to undulate, apex acuminate;

stamens prominent, slightly recurved-spreading to straight, 10–18 mm;

filaments white, shorter than anthers, slender;

anthers yellow, 4–16 mm, slender, dehiscence latrorse-introrse;

ovary green or white, ovoid, 6-angled, 5–12 mm, attachment ± 3/4 ovary width;

stigmas recurved, barely connate basally, greenish white or white, linear, not lobed adaxially, 6–10 mm, uniformly thin;

pedicel erect to leaning, 2–6 cm.

in axil of bracts at or near ground level, ± erect, odor unknown;

sepals erect to widely spreading, often weakly recurved near middle, green, oblong-elliptic to oblanceolate, 22–47 × 7–10 mm, margins entire, apex acute;

petals long-lasting, ± connivent, ± concealing stamens and ovary, or erect-spreading early then ± connivent, erect to incurved, light maroon-red, purple, or greenish to yellowish, not spirally twisted, flat, linear-lanceolate, 3–5.5 × 0.4–1 cm, thick-textured, margins entire, apex acute;

stamens erect, (15–) 22–30 mm;

filaments olive, (3–)5–7 mm, slender;

anthers straight, brown or olive, 16–20 mm, slender, dehiscence latrose;

connectives yellow or orange, ± not extending beyond anther sacs;

ovary white, greenish, purplish distally, ovoid, sharply angled, 4–9 mm;

stigmas erect, divergent, distinct, purple or olive, linear-subulate, 7–20 mm, apex somewhat recurved.

Fruits

baccate, green or white, ± odorless, broadly ovoid, obscurely winged, 1.2–2.8 × 0.7–1.9 cm, pulpy-moist.

fragrance not reported, ovoid, strongly angled/winged, ca. 1 cm, pulpy, moist.

2n

= 10.

= 10.

Trillium ovatum

Trillium petiolatum

Phenology Flowering spring (early Apr–late May).
Habitat Lower rocky hillsides just above stream flats, under brush, edges of coniferous and deciduous forests, open grassy glades, river-flats, wet, seasonally swampy ground and edges of sloughs
Elevation 400–1400 m (1300–4600 ft)
Distribution
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Bracts sessile; petals lanceolate to obovate, 1.5–7 × 1–4 cm
var. ovatum
1. Bracts distinctly short-petiolate; petals linear to linear-lanceolate, 0.5–2.4 × 0.2–0.6 cm
var. oettingeri
Source FNA vol. 26, p. 100. FNA vol. 26, p. 113.
Parent taxa Liliaceae > Trillium > subg. Trillium Liliaceae > Trillium > subg. Phyllantherum
Sibling taxa
T. albidum, T. angustipetalum, T. catesbaei, T. cernuum, T. chloropetalum, T. cuneatum, T. decipiens, T. decumbens, T. discolor, T. erectum, T. flexipes, T. foetidissimum, T. gracile, T. grandiflorum, T. kurabayashii, T. lancifolium, T. ludovicianum, T. luteum, T. maculatum, T. nivale, T. parviflorum, T. persistens, T. petiolatum, T. pusillum, T. recurvatum, T. reliquum, T. rivale, T. rugelii, T. sessile, T. simile, T. stamineum, T. sulcatum, T. underwoodii, T. undulatum, T. vaseyi, T. viride, T. viridescens
T. albidum, T. angustipetalum, T. catesbaei, T. cernuum, T. chloropetalum, T. cuneatum, T. decipiens, T. decumbens, T. discolor, T. erectum, T. flexipes, T. foetidissimum, T. gracile, T. grandiflorum, T. kurabayashii, T. lancifolium, T. ludovicianum, T. luteum, T. maculatum, T. nivale, T. ovatum, T. parviflorum, T. persistens, T. pusillum, T. recurvatum, T. reliquum, T. rivale, T. rugelii, T. sessile, T. simile, T. stamineum, T. sulcatum, T. underwoodii, T. undulatum, T. vaseyi, T. viride, T. viridescens
Subordinate taxa
T. ovatum var. oettingeri, T. ovatum var. ovatum
Name authority Pursh: Fl. Amer. Sept. 1: 245. (1814) Pursh: Fl. Amer. Sept. 1: 244. (1814)
Web links