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

painted lady, painted trillium, painted wakerobin, trille ondulé

Rhizomes

horizontal, brownish, thick, praemorse, fleshy.

horizontal, short, stout, ± praemorse.

Scapes

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

1–3, dark greenish maroon, round in cross section, 1.1–4 dm, 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).

strongly petiolate;

blade dark green over maroon, main veins prominent, ovate to long-acuminate, 12–18 × 8–20 cm, ± glossy, base above petiole rounded, apex acuminate;

petiole 4–17 mm.

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.

opening above bracts, erect, odor unknown;

sepals conspicuous, spreading, wine red to dull maroon green, rarely white-striated, lanceolate-acuminate, 13–37 × 4–10 mm, margins entire, apex acuminate;

petals spreading, white, with distinct, inverted, V-shaped, dark-red mark basally, the red radiating outward along major veins, or white and lacking red marks, veins not engraved, oblong-ovate, occasionally lanceolate, usually widest just above middle, 2–5 × 1–2 cm, base tapering very gradually to attachment, margins not undulate basally, undulate apically, apex somewhat rapidly acuminate;

stamens straight, 8–12 mm;

filaments pink or white, equaling or longer than anthers, slender;

anthers erect or slightly spreading, white or pink, 2–7 mm, thin, dehiscence extrorse;

connectives pink, equaling anther sac;

ovary fully exposed, white, pink tipped, obtusely 3-angled, becoming obscurely angled-rotund in cross section, 3–10 mm, broadly attached;

stigmas ascending, barely connate basally, then strongly recurved, white, ± linear, 3–10 mm, uniformly thin;

pedicel erect, 2–5 cm.

Fruits

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

quickly deciduous upon ripening, scarlet, obscurely 3-angled to cylindrical, 1–2 cm, fleshy, juicy.

2n

= 10.

= 10.

Trillium sessile

Trillium undulatum

Phenology Flowering spring (Mar–early May). Flowering late spring–early summer (late Apr–Jun).
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 Deep acid humus of pine, spruce, hemlock, oak, mixed deciduous-coniferous woods, rhododendron or mountain laurel thickets in s range, almost any acidic forested situation n and ne, often around old Pinus strobus stumps in white birch-red maple-white pine second-growth woods in n range, prefers deep shade except at high elevations in range, not usually found on limestone-derived or basic soils unless in very deep acid humus
Elevation 100–300 m (300–1000 ft) 10–1800 m (0–5900 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
CT; GA; KY; MA; MD; ME; MI; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WV; NB; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

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

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

Several forms of Trillium undulatum have been described. One, forma enotatum T. S. Patrick, lacks the usual red, V-shaped petal markings. Other named forms have green petals, extra leaves or petals, and deformities suggesting a mycoplasma infection as in Trillium grandiflorum.

This difficult-to-cultivate species has been reported from Wisconsin, but it cannot be accepted as native there.

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

Source FNA vol. 26, p. 115. FNA vol. 26, p. 105.
Parent taxa Liliaceae > Trillium > subg. Phyllantherum Liliaceae > Trillium > subg. Trillium
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. 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. vaseyi, T. viride, T. viridescens
Synonyms T. erythrocarpum
Name authority Linnaeus: Sp. Pl. 1: 340. (1753) Willdenow: Ges. Naturf. Freunde Berlin Neue Schriften 3: 422. (1801)
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