keys to the vascular plants of east texas - Botanical Research ...

TRILLIUM/TRILLIACEAE 1133
taxonomic confusion (Cabe 1995; Zomlefer 1996). Freeman (1975), for example, indicated that
petal color “… should be considered one of the least reliable criteria (except in certain cases) by
which to distinguish species within the sessile-flowered group [of Tr illium].” Likewise, absolute
size of structures does not appear reliable in distinguishing taxa (Freeman 1975). All species of
Trillium occurring in TX are found in or near the Pineywoods. The common name WAKE-ROBIN
is possibly in reference to the often early spring flowering period. (Latin: tri, three, in reference
to the number of bracts or the flower parts in threes)
REFERENCES: Gates 1917; Peattie 1927; Barksdale 1938; Freeman 1969, 1970, 1975; Nixon et al. 1970;
Takahashi 1982; Samejima & Samejima 1987; Les et al. 1989; Mitchell 1989, 1990; Cabe 1995, Cabe
& Werth 1995; Kato et al. 1995a, 1995b; Kawano & Kato 1995; Zomlefer 1996; Case & Case 1997;
Tamura 1998d; Kazempour Osaloo & Kawano 1999; Kazempour Osaloo et al. 1999; Irwin 2000;
Case 2002; Singhurst et al. 2002b; Timmerman-Erskine et al. 2002.
1. Flowers on pedicels 2–4 cm long; petals white or pink (reddish with age), spreading-ascending,
exposing the stamens and ovary; stigmas on a distinct style; leaf-like bracts not mottled ________ T. pusillum
1. Flowers sessile or essentially so; petals purple, greenish, or yellow, erect or erect-spreading, �
concealing the stamens and ovary; stigmas sessile; leaf-like bracts mottled or not mottled.
2. Leaf-like bracts petiolate; filaments usually ca. as long as anthers; sepals (at flowering time)
reflexed at base; rhizomes slender, the length of the internodes ca. equal to the rhizome diam.,
whitish; anther connectives strongly incurved ______________________________________ T. recurvatum
2. Leaf-like bracts sessile; filaments usually much shorter than anthers; sepals various but not
reflexed at base; rhizomes stout, the length of the internodes 1/5 or less the rhizome diam.,
brownish; anther connectives erect or slightly incurved.
3. Petals purple, rarely yellow, 2–4 cm long; ovary 3-angled; anther dehiscence introrse (=
facing inward) _________________________________________________________________ T. gracile
3. Petals greenish purple or greenish, with a purple claw, sometimes purple or yellowish green
throughout, 3.5–8.5 cm long; ovary 6-angled; anther dehiscence lateral.
4. Leaf-like bracts usually distinctly mottled, lacking stomata on upper leaf epidermis; scapes
glabrous; stamens ca. 1/4 taller than height of gynoecium; stigmas divergent-erect, the
tips rarely, if ever, extending between the stamens; plants usually � 31 cm tall
____________________________________________________________________ T. ludovicianum
4. Leaf-like bracts not mottled or only obscurely mottled, sometimes (not usually) with
stomata on upper leaf epidermis at the apex (visible as tiny white speckles under magnification);
scapes usually scabrous near leaf-like bracts; stamens ca. 2–2.5+ times the
height of gynoecium; stigmas widely spreading, often with the tips extending between
the stamens; plants usually � 30 cm tall ______________________________________ T. viridescens
Trillium gracile J.D. Freeman, (slender, gracefully slight in form), SLENDER TRILLIUM, SLENDER
WAKE-ROBIN, GRACEFUL TRILLIUM. Plant to 32.5(–36) cm tall, usually not in dense clumps; leaflike
bracts elliptic to elliptic-ovate or obovate, 6–10 cm long, rounded to acute, sessile, usually
distinctly mottled; flowers sessile, with odor musty or like that of a morel fungus; sepals widely
spreading and reflexed at tips, usually dark purple on adaxial surface, 15–26 mm long; petals
erect, usually dark purple or rarely yellow, linear-elliptic or linear-oblanceolate; 21–40 mm
long; stamens usually slightly less than 2 times the height of the gynoecium; anthers 10–15 mm
long; ovary 3-angled; fruit not obviously angled. Sandy loam of rich hardwood-pine and pine
forests on slopes and stream banks; Jasper, Newton, Sabine, San Augustine, Shelby, Tyler
(BAYLU), Hardin, Jasper, Nacogdoches, Newton, Sabine, and San Augustine (BRIT), Angelina,
San Jacinto, Shelby (TOES 1993), Jefferson and Nacogdoches (Singhurst et al. 2002b) cos. in the
Pineywoods; endemic to se TX and sw LA (Mitchell 1989; Singhurst et al. 2002b). Late Mar–May.
[T. ludovicianum of authors in part, not Harb.] This species was described by Freeman in 1969
based on specimens from East TX and adjacent LA; the holotype is from Sabine Co. Individuals
with petals yellow or greenish yellow (lacking purple pigmentation) occur with more typical