Trillium ovatum


Fl. Amer. Sept. 1: 245. 1814.

Common names: Western white trillium white trillium
Treatment appears in FNA Volume 26. Treatment on page 100. Mentioned on page 93, 96, 97.

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).

Selected References



1 Bracts sessile; petals lanceolate to obovate, 1.5–7 × 1–4 cm Trillium ovatum var. ovatum
1 Bracts distinctly short-petiolate; petals linear to linear-lanceolate, 0.5–2.4 × 0.2–0.6 cm Trillium ovatum var. oettingeri