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sessile trillium, sessile-flower wake-robin, toad trillium, toadshade

giant purple wakerobin

Rhizomes

horizontal, brownish, thick, praemorse, fleshy.

horizontal, brownish, thick, praemorse, not brittle.

Scapes

1–3, round in cross section, 0.8–2.5 dm, slender to stout, glabrous.

often 2 from single terminal bud, round in cross section, 2.5–5.5 dm, stout, glabrous.

Bracts

held well above ground, sessile;

blade green to bluish green, strongly to sparsely mottled, mottling becoming obscure with age, oval to suborbicular, 4–10 × 2–8 cm, base broadly attached, apex rounded-acuminate to bluntly parallel sided-acuminate (rounded basally to its broad attachment).

held well above ground, sessile;

blade bright green (in early anthesis rather succulent in appearance), usually well-marked with lighter and darker green spots, occasionally obscurely or scarcely mottled, mottling becoming obscure with age, ovate to broadly ovate, 11–18 × 12–17 cm, somewhat glossy, apex acuminate.

Flower

erect, odor pungent, spicy;

sepals displayed above bracts, spreading, green, variously streaked with maroon, lanceolate-oblanceolate, 9–35 × 4–8 mm, margins entire, apex rounded-acuminate;

petals long-lasting, erect, ± connivent, ± concealing stamens and ovary, maroon, brownish maroon, green, or yellowish green, not spirally twisted, oblanceolate to elliptic, occasionally almost orbicular, 1.7–3.5 × 0.7–2 cm, thick-textured, narrowed near basal attachment (but not truly clawed), margins entire, apex gradually rounded-tapered to acute;

stamens straight, 10–23 mm;

filaments red-purple, 2–5 mm, dilated basally;

anthers erect, straight, gray-purple, 9–16 mm, thick, dehiscence introrse;

connectives purplish brown, straight, projecting 2–5+ mm beyond anther sacs;

ovary greenish white basally, purple distally, ovoid to globose, 6-angled, pyramidally narrowed to stigmas, 4–8.5 mm;

stigmas erect, divergent-recurved, distinct, purple, subulate, 1–5 mm, ± fleshy.

odor spicy in fresh flowers, becoming fetid in older flowers;

sepals displayed above bracts, spreading, divergent, green, purple-streaked, lanceolate, 40–75 × 10–14 mm, margins entire, apex acute to round-acute;

petals long-lasting, conspicuous, spreading-erect to erect, tips incurving slightly, ± connivent, partially to completely concealing stamens and ovary, glossy dark maroon-red or purple, not spirally twisted, flat, oblanceolate, 5.5–11 × 2–3.5 cm, widest at or below middle, glossy, thick-textured, cuneate basally, margins ± flat, entire, apex round-acute;

stamens erect, straight, 15–26 mm, slightly concealing ovary;

filaments dark purple, 2–4 mm;

anthers dark maroon, 13–24 mm, dehiscence introrse;

connectives straight, barely extended beyond anther sacs;

ovary inconspicuous, purple, ovoid, round to 6-angled, 8–15 mm;

stigmas erect, distinct, subulate, 6–8 mm, fleshy, thickened basally.

Fruits

baccate, dark greenish purple, odorless, subglobose, 6-angled, angles somewhat winglike, pulpy, not juicy.

dark reddish purple, ovoid to ellipsoid or weakly angled, 20–50 mm, fleshy.

2n

= 10.

Trillium sessile

Trillium kurabayashii

Phenology Flowering spring (Mar–early May). Flowering spring (late Mar–early May).
Habitat Rich woodlands, limestone districts, calcareous soils, floodplains, riverbanks, clayey alluvium, less fertile soils, high, dry limestone woods, persists under light pasturing, in fencerows and brushy areas after lumbering Rich, moist conifer-hardwood forest, slopes, especially lower slopes, predominantly deciduous flat woods along streams, edges of Sequoia groves, and alder, vine maple, and fern thickets along streams, especially older, higher flood terraces, not the lowest and wettest, at higher elevations, both in forests and in open grassy meadows with scattered oak trees
Elevation 100–300 m (300–1000 ft) 20–500+ m (100–1600+ ft)
Distribution
from FNA
AL; AR; IL; IN; KS; KY; MD; MI; MO; NC; NY; OH; OK; PA; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
Discussion

Trillium sessile is rather uniform throughout its range, with few color forms.

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

Source FNA vol. 26, p. 115. FNA vol. 26, p. 110.
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. 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. petiolatum, T. pusillum, T. recurvatum, T. reliquum, T. rivale, T. rugelii, 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. 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
Name authority Linnaeus: Sp. Pl. 1: 340. (1753) J. D. Freeman: Brittonia 27: 56, fig. 12. (1975)
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