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Trillium ovatum

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

decumbent trillium, trailing wakerobin

Rhizomes

semierect to horizontal, short, stout, praemorse.

short, thick.

Scapes

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

1–2, decumbent, usually by an S-shaped curvature, round in cross section, 0.5–2 dm, somewhat stout, slightly expanded toward bracts, densely puberulent, especially just below bracts and on bases of main bract veins beneath.

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.

appearing early in season, in good condition for only a few weeks after anthesis, dying back to semipersistent bases early, resting on ground surface, sessile;

blade strongly mottled in shades of green and bronze and with silvery overlay, mottling becoming obscure with age, ovate to suborbicular, 4–12 × 3.3–7 cm, apex acute to rounded.

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.

erect, odor unreported;

sepals divergent, green- or maroon-streaked, lanceolate-ovate, 22–48 × 9–14 mm, margins entire, flat, apex acute;

petals long-lasting, rigidly erect, ± connivent, ± concealing stamens and ovary, dark maroon-purple when fresh, fading especially distally to dull reddish brown, greenish brown, or with creamy yellow tones, very rarely pale lemon yellow forms occur, twisted (but not spiraled), linear-lanceolate or oblanceolate, 4–8+ × 0.7–1 cm, thick-textured, margins entire, apex acute;

stamens erect, straight, dark purple, 10–25 mm;

filaments dark purple, 2–5 mm;

anthers straight, dark purple, 9–20 mm, dehiscence extrorse;

connectives broad, extending to 3.5–4 mm beyond anther sacs;

ovary dark purple, oval, 6-angled, 5–10 mm;

stigmas erect, divergent-recurved, distinct, sessile, pink or white, subulate, 4.5–8 mm.

Fruits

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

baccate, dark purple, broadly ovoid to subglobose, crownlike, strongly ridged, 1–1.5 × 1 cm, pulpy but not juicy, present and enlarging on naked scapes until early autumn.

2n

= 10.

= 10.

Trillium ovatum

Trillium decumbens

Phenology Flowering late winter–spring (mid Mar–Apr).
Habitat Thin, open rocky wooded slopes, mature deciduous woodlands, rocky talus and disintegrating shale, flats (floodplains) of small streams and adjacent slopes near river entrance
Elevation 50–200 m (200–700 ft)
Distribution
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; GA; TN
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Trillium decumbens occurs in the Ridge and Valley and Cumberland Plateau physiographic provinces. It has a large, deep, horizontal rhizome, the growing point of which always faces downslope.

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

Key
1. Bracts sessile; petals lanceolate to obovate, 1.5–7 × 1–4 cm
T. ovatum var. ovatum
1. Bracts distinctly short-petiolate; petals linear to linear-lanceolate, 0.5–2.4 × 0.2–0.6 cm
T. ovatum var. oettingeri
Source FNA vol. 26, p. 100. FNA vol. 26, p. 109.
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. 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. 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
Subordinate taxa
T. ovatum var. oettingeri, T. ovatum var. ovatum
Name authority Pursh: Fl. Amer. Sept. 1: 245. (1814) Harbison: Biltmore Bot. Stud. 1: 158. (1902)
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