Trillium cernuum
Trillium luteum
nodding trillium, nodding wakerobin, trille penché, whip-poor-will-flower
wax trillium, yellow toadshade, yellow trillium, yellow wakerobin
short, thick.
horizontal, brownish, short, thick, praemorse, not brittle.
1–2(–3), round in cross section, 1.5–4+ dm, slender, glabrous.
1–4, round in cross section, 1.4–4 dm, stout, glabrous.
often overlapping, sessile or with a barely noticeable, petiolelike base, umbrellalike;
blade bright green without red tones, broadly rhombic-ovate to suborbicular, 5–15 × 6–15+ cm, base attenuate, apex acuminate.
held well above ground, sessile;
blade mottled, mottling becoming more obscure as growth matures, shape variable, ovate-elliptic to ± orbicular-acuminate, 6.5–17 × 6.5–9.8 cm, not glossy, apex acuminate to long-acuminate.
usually hidden beneath bracts, nodding, odorless;
sepals spreading, green, lanceolate-ovate, 9–30 mm, slightly shorter than to equaling petals, margins slightly raised, apex acuminate;
petals usually strongly recurved from above base, extending behind plane of sepal bases for more than 1/2 their length, white or rarely pale pink, adaxial veins not conspicuous, oblong-lanceolate, 1.5–2.5 × 0.9–1.5 cm, thin-textured, margins entire, apex acuminate;
stamens ± straight, 6–15 mm, shorter than pistil, slender;
filaments white, ± equaling anthers, slender;
anthers straight, pale lavender-pink or -gray, 2–6.5 mm, dehiscence introrse to latrorse;
ovary prominent, white to pinkish, pyramidal, strongly 6-angled, 3–12 × 3–10 mm, widest above basal attachment;
stigmas erect, recurved, distinct, white, not lobed adaxially, 3–8 mm, widest at base, fleshy, basally thickened, gradually tapered;
pedicel strongly recurved or declined below or angled between bracts, 1.5–3 cm.
erect, odor strongly lemony;
sepals displayed above bracts, widely spreading, green, oblong-lanceolate, lanceolate, or oblong-elliptic, 22–47 × 8–9 mm, margins entire, apex distinctly rounded-acute;
petals long-lasting, erect, ± connivent, ± concealing stamens and ovary, greenish yellow to lemon yellow, not spirally twisted, not clawed, elliptic-lanceolate, lanceolate, or oblanceolate, 3.4–6.6 × 1–2.1 cm, thick-textured, widest near base, margins entire, tapering to long-acuminate apex;
stamens erect, 11–18 mm;
filaments greenish white, 1.5–2 mm, basally dilated;
anthers erect, straight, yellow, 9–16 mm, dehiscence introrse (or appearing lateral);
connectives green, straight, broad, extending only slightly (to 0.5 mm) or not at all beyond anther sacs;
ovary pale green, ovoid to globose, 6-angled, 5–8 mm;
stigmas erect, barely spreading, distinct, greenish white, sessile, linear to subulate, 3–4 mm, fleshy.
dark red, with fruity fragrance, ovoid, to 3 cm diam., fleshy, juicy.
green to greenish white, occasionally with dark streaks, odor not reported, ovoid, 6-angled, 3.5 × 2 cm, pulpy.
= 10.
= 10.
Trillium cernuum
Trillium luteum
Previous authors commonly recognized var. cernuum and var. macranthum, based primarily upon size differences. Plants attributed to var. cernuum are found from Delaware and eastern Pennsylvania northward to Newfoundland, while those attributed to var. macranthum are found mainly farther inland into the Midwest. Although there is a tendency for the eastern seaboard plants to be somewhat smaller and more delicate, and the midwestern and far northern plants to be more robust, there is much variation, largely dependent on soil nutrients. There are regional size trends, but based on my observations of this species in Newfoundland, Michigan, Wisconsin, and Minnesota, I do not believe that the two varieties can be maintained.
In the Gray Herbarium, there is a collection by Richardson labeled “Mackenzie River,” which has been cited by H. M. Raup (1947) and others. W. J. Hooker ([1829–]1833–1840) reported Trillium cernuum “from Saskatchewan to Mackenzie River.” Raup stated that “it is the only evidence for the occurrence of...Trillium in the entire Mackenzie Basin.” Other writers have simply quoted that statement. In view of the relatively great disjunction from the known Saskatchewan stations and in the absence of any other supporting specimens from that area, I believe that there might be locality error on the Richardson sheet. However, it is not beyond possibility that T. cernuum could occur there. This apparent disjunct station is not mapped here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Botanists have been confused by Trillium luteum for a long time. Some, such as A. E. Radford et al. (1968), appear to regard it as a form of T. cuneatum, while others confuse it with T. viride, a more western species. Early botanists confused T. luteum with the occasional individual or very local larger population of pallid color forms of other species. Trillium cuneatum rather frequently produces green, yellowish green, or pale lemon yellow forms (but with a cuneate larger and wider petal) that mimic T. luteum. These forms, when growing with T. luteum, hybridize, leading to so many intergrades that many plants cannot be placed in either species with any confidence. For these reasons, almost no work older than J. D. Freeman’s (1975) can be used reliably to plot distribution of T. luteum.
In some parts of their ranges, Trillium luteum and T. cuneatum do not grow together. Trillium luteum is abundant in eastern Tennessee, extending a short distance into North Carolina and Georgia. Trillium cuneatum is rare or absent from this region except along the Little Tennessee River (J. D. Freeman 1975).
Trillium luteum has escaped and become established along the Grand and Saint Joseph rivers and elsewhere in Michigan, near Kingston and Grimsby, Ontario (J. K. Morton pers. comm.), and probably elsewhere.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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