Trillium sessile |
Trillium petiolatum |
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sessile trillium, sessile-flower wake-robin, toad trillium, toadshade |
Idaho trillium, long-petioled trillium, petioled wakerobin, purple trillium, purple wakerobin, round-leaf trillium |
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Rhizomes | horizontal, brownish, thick, praemorse, fleshy. |
± erect, often very deep, praemorse. |
Scapes | 1–3, round in cross section, 0.8–2.5 dm, slender to stout, glabrous. |
typically 1, vertical but mostly subterranean, round in cross section, 0.4–1.7 dm, robust, 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). |
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 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. |
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 greenish purple, odorless, subglobose, 6-angled, angles somewhat winglike, pulpy, not juicy. |
fragrance not reported, ovoid, strongly angled/winged, ca. 1 cm, pulpy, moist. |
2n | = 10. |
= 10. |
Trillium sessile |
Trillium petiolatum |
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Phenology | Flowering spring (Mar–early May). | Flowering spring (early Apr–late 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 | 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 | 100–300 m (300–1000 ft) | 400–1400 m (1300–4600 ft) |
Distribution |
AL; AR; IL; IN; KS; KY; MD; MI; MO; NC; NY; OH; OK; PA; TN; VA; WV
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ID; OR; WA
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Discussion | Trillium sessile is rather uniform throughout its range, with few color forms. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 26, p. 115. | FNA vol. 26, p. 113. |
Parent taxa | Liliaceae > Trillium > subg. Phyllantherum | Liliaceae > Trillium > subg. Phyllantherum |
Sibling taxa | ||
Name authority | Linnaeus: Sp. Pl. 1: 340. (1753) | Pursh: Fl. Amer. Sept. 1: 244. (1814) |
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