7. Trillium ovatum Pursh, Fl. Amer. Sept. 1: 245. 1814.
Western white trillium, white trillium
Rhizomes semierect to horizontal, short, stout, praemorse. Scapes 1–2, round, 2–5 dm, ± slender, 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. 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. Fruits baccate, green or white, ± odorless, broadly ovoid, obscurely winged, 1.2–2.8 × 0.7–1.9 cm, pulpy-moist. 2n = 10.
Varieties 2 (2 in the flora): w North America.