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decumbent trillium, trailing wakerobin

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

Rhizomes

short, thick.

± erect, often very deep, praemorse.

Scapes

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.

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

Bracts

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.

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, 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.

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, 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.

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

2n

= 10.

= 10.

Trillium decumbens

Trillium petiolatum

Phenology Flowering late winter–spring (mid Mar–Apr). Flowering spring (early Apr–late May).
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 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 50–200 m (200–700 ft) 400–1400 m (1300–4600 ft)
Distribution
from FNA
AL; GA; TN
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Source FNA vol. 26, p. 109. FNA vol. 26, p. 113.
Parent taxa Liliaceae > Trillium > subg. Phyllantherum Liliaceae > Trillium > subg. Phyllantherum
Sibling taxa
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
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
Name authority Harbison: Biltmore Bot. Stud. 1: 158. (1902) Pursh: Fl. Amer. Sept. 1: 244. (1814)
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