Trillium undulatum

Rhizomes horizontal, short, stout, ± praemorse. Scapes 1–3, dark greenish maroon, round in cross-section, 1.1–4 dm, glabrous. Bracts 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 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 quickly deciduous upon ripening, scarlet, obscurely 3-angled to cylindrical, 1–2 cm, fleshy, juicy. 2n = 10.

Phenology: Flowering late spring–early summer (late Apr–Jun).
Habitat: 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: 10–1800 m

N.B., N.S., Ont., P.E.I., Que., Conn., Ga., Ky., Maine, Md., Mass., Mich., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va.

Discussion

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.

Selected References

None.

Lower Taxa