The genus Trillium in the Southeast John D. Freeman 1a Flower pedicellate (or if sessile, flower white to pink and plant agreeing with both of the following conditions); leaves uniformly green, unmottled; stigmas united into a short style or sessile. . . . . . . . . . . . . . . . . . . . . . . .2 1b. Flower sessile; leaves mottled (rarely obscurely) with 2 or more shades of green, the shades fading with age; stigmas strictly sessile, common style lacking . . . . . . . . . . . . . . . . . . . . . . 14 2a Petals smooth-textured, delicate, more or less undulate, white to deep ink (often white changing to pink upon aging); stigmas thin, uniform in diameter, often fused into a short style; ovary pale green to white . . . . . . . . . . . . . . . . .3 2b Petals usually veiny; straight margined, purple to white (if white, changing to brown, never pink, upon aging); stigmas thicker at base, somewhat subulate, distinct; ovary purple-black, pinkish or white . . . . . . . . . . . . . . . . . . .8 3a Petals white with a purplish V-shaped blaze near base (rarely uniformly white or pink); anther sacs lavender to white, extrorse in position and dehiscence; fruit a red berry . . . . . . T. undulatum 3b Petals white, changing to deep pink with age; anther sacs yellow, introrse to latrorse in position and dehiscence; fruit a white to greenish white fleshy capsule. . . . . . . . . . . . .4 4a Pedicel declined below leaves (rarely erect); anthers irregularly curved or twisted outward; pollen bright yellow . . . . . . . . . . . T. catesbaei 4b Pedicel erect or inclined above leaves; anthers straight, erect or divergent; pollen pale yellow . . .5 5a Sepals as wide or wider than petals, rounded at apex; anther connectives usually purplish between anther sacs; pedicel erect through fruiting, or absent . . . . . . . . . . . . . . . . . . .T. pusillum 5b Sepals narrower than petals, pointed at the apex; anther connectives usually purplish between anther sacs; pedicel often somewhat inclined . . . . .6 6a Ovary obscurely 3 lobed; leaves less than 5 cm long, blue-green, rounded at apex; (plant less than 2 dm tall) . . . . . . . . . . . . . . .T. nivale 6b Ovary 6-winged; leaves more than 5 dm long, green, pointed at apex; plant more than 2 dm tall . . . . . . . . . . . . . . . . . . . . . . . . . . .7 7a Petals obovate, tightly inrolled at base, flaring apically; leaves broadly elliptic, acuminate; style obscure, less than 1.0 mm long . .T. grandiflorum 7b Petals elliptic, loose, gradually separating; leaves narrowly ovate, acute; style conspicuous, more than 1.5 m long . . . . . . . . . . .T. persistens 8a Pedicel abruptly declined below leaves; leaves shot-petiolate; petals strongly recurved, extending about half or more their length between sepals . . . . . . . . . . . . . . . . . . . . . . . .9 8b Pedicel declined, inclined or erect; leaves sessile to sub-sessile; petals ringent to widely spreading, recurved only toward apex if at all . . . 11 9a Stamens much longer than pistil height, the maroon filaments as long as or longer than ovary and the anther sacs yellow to maroon; ovary globose, relatively small; leaves elliptic . .T. vaseyi 9b Stamens usually shorter than pistil, at most 1.5X longer, the white filaments shorter than ovary and the anthers sacs lavender to vivid purple (unless albino); ovary angular-ovoid, relatively large; leaves broadly elliptic to obovate. . . . . . 10 10a Anthers 7.5 mm or less long, equaling the filaments or shorter petals narrowly elliptic to obovate, often scarcely larger than sepals . T. cernuum 10b Anthers 7.0 mm or more long, longer than filaments; petals ovate to elliptic, larger and much wider than sepals . . . . . . . . . . . T. rugelii 11a Anthers creamy white, 2-5x as long as filaments; ovary white to pink, widest near base; stigmas prominent, nearly as long as ovary . . . . .T. flexipes 11b Anthers mostly yellowish to purplish, rarely creamy white, at most 2.2X as long as filaments; ovary purple-black o maroon (unless albino), subglobose; stigmas small, less than 1/2 as long as ovary . . . . . . . . . . . . . . . . . . . . . . . 12 12a Petals lanceolate to narrowly ovate or elliptic, usually less than 2X as wide as sepals and spreading in the same plane with them; sepals 1/2 or more as long as pedicel, weakly sulcate near apex . . . . . . . . . . . . . . . . . . . . T. erectum 12b Petals ovate, more than 2X as wide as sepals and often ringent, variably recurved apically; sepals usually 1/2 or less as long as pedicel, distinctly sulcate at apex . . . . . . . . . . . . . 13 13a Leaves broadly elliptic, the flowers relatively large in proportion to them; petals white, much longer than sepals; sepals green, 0.4-0.7 as long as pedicel . . . . . . . . . . . . . . . . . .T. simile 13b Leaves broadly obovate, the flowers relatively small in proportion to them; petals usually reddish purple (in some populations pinkish, yellowish, or creamy white), slightly longer than sepals; sepals suffused with purple, 0.2-0.4 as long as pedicel . . . . . . . . . . . . . .T. sulcatum 14a Sepals reflexed from base, often to a vertical alignment with stem below the leaves; filaments about as long as anther connectives, the latter strongly incurved; rhizome relatively slender, the length of an internode about equal to the diameter . . . . . . . . . . . . . . . . . . . . . . 15 14b Sepals divergent to spreading above leaves, sometimes reflexed near middle; filaments much shorter than anther connectives, the latter erect to slightly incurved; rhizome stocky, the length of an internode 1/5 or less the diameter . . . . . . 16 15a Leaves distinctly petiolate, the petioles ascending and blades spreading; petals about 2X as long as wide, arched inward . . . . . .T. recurvatum 15b Leaves sessile or subsessile, spreading horizontally below flower level (thus sometimes preventing sepals from fully recurving); petals 4X or more as log as wide, more or less erect T. lancifolium 16a Inner surface of anther connective wider than outer, the anther sacs and pollen dehiscence thus extrorse; stems usually pilose or puberulent. . . . 17 16b Inner surface of anther connective narrower than or equal to the outer, the anther sacs and pollen dehiscence thus introrse to latrorse; stem usually glabrous or scabrous . . . . . . . . . . . . 18 17a Stem erect, pilose near leaves (rarely glabrous); petals horizontal, narrowly elliptic to linear, strongly twisted, 2X or less as long as stamens; pollen brownish (except in yellow forms) . T. stamineum 17b Stem decumbent, densely puberulent; petals erect, narrowly elliptic-oblanceolate, slightly twisted, 3-5X as long as stamens; pollen yellow . . T. decumbens 18a Anther sacs introrse, pollen dehiscence oriented toward pistil . . . . . . . . . . . . . . . . . . . 19 18b Anther sacs latrorse, pollen dehiscence oriented toward adjacent stamens. . . . . . . . . . . . . . . 26 19a Stamens 2X or more as long as pistil; stigmas divergent or spreading . . . . . . . . . . . . . . . 20 19b Stamens 1.5X or less as long as (sometimes shorter than) pistil; stigmas erect. . . . . . . . . 22 20a Stem at least partially decumbent in an open S- shaped curve, usually less than 2X as long as the leaves; petals narrowly elliptic-oblanceolate T. reliquum 20b Stem erect, straight, usually more than 2X as long as leaves; petals spatulate or linear- elliptic . . . . . . . . . . . . . . . . . . . . . . 21 21a Petals spatulate, apiculate, pale ivory yellow above greenish to maroon claws; anther connectives prolonged into short beaks, 1.0-1.5 mm long. . . . . . . . . . . . . . . . . . .T. discolor 21b Petals linear-elliptic, acute to rounded, purple (rarely yellow); anther connectives prolonged 1.0 mm or less . . . . . . . . . . . . . . . . . T. gracile 22a Stamens about 1/2 as long as petals; anther connectives prolonged into distinct beaks 1-5 mm long . . . . . . . . . . . . . . . . . . . . . . . . 23 22b Stamens 1/3 as long as petals; anther connectives scarcely prolonged, beaks (if present) rarely as long as 1 mm . . . . . . . . . . . . . . . . . . . . 24 23a Ovary subglobose, narrowed apically into bases of slender stigmas 1.5-2.0X its length; connective beak about as long as filament, longer than connective width . . . . . . . . . . . . . . T. sessile 23b Ovary ovoid, somewhat constricted blow bases of thickly Subulate stigmas about as long as ovary; connective beak 1/2 or less as long as filament, equal to or shorter than connective width T. foetidissimum 24a Petals narrowly spatulate, mostly 4.5X or more as long as wide; ovary 3-angled (rarely hexagonal) at base of stigmas . . . . . . . . . . . . T. maculatum 24b Petals elliptic-oblanceolate to oblanceolate, broadly or narrowly so, mostly less than 4X as long as wide; ovary hexagonal or 6-ridged at base of stigmas . . . . . . . . . . . . . . . . . . . . . 25 25a Flowers mostly with some purple pigments, banana- scented, rarely musky; petals brownish purple, bronze, green, pale yellow, bicolored or otherwise; portions of ovary and stamens purplish . . . . . . . . . . . . . . . . . . . . . .T. cuneatum 25b Flowers without purple pigments, lemon-scented; petals greenish yellow darkening to yellow; ovary and stigmas greenish white . . . . . . . . . .T. luteum 26a Ovary ellipsoid, sharply 6-angled or -winged by narrow, deep dorsal grooves about 1/3 as wide as the relatively flat sides along carpel sutures; stigmas short, 1/2 or less as long as ovary, abruptly and tightly recoiled; anther connective distinctly prolonged (0.5-) 1.0-1.5 (-3.5) mm, the beak about as log as the filament . . . . . . . 27 26b Ovary ovoid, hexagonal or 6-ridged by wide, sallow dorsal grooves, the dorsal faces about as wide as the faces along carpel sutures; stigmas long, about as long as ovary, divergent or spreading, recurved at apex if at all; anther connective scarcely prolonged, rarely more than 0.5 mm, the beak (if present) much shorter than filament . . . . . . . . . . . . . . . . . . . . . . 28 27a Stems usually less than 2X as long as leaves; petals elliptic-oblanceolate, usually purple, mostly more than 4X as long as wide . . T. underwoodii 27b Stems usually more than 2.5X as long as leaves; petals obovate, usually greenish, mostly less than 3X as long as wide . . . . . . . . . T. decipiens 28a Petals linear-spatulate or very narrowly oblanceolate, mostly 5.5X as long as wide and more or less clawed, the claws usually purple and blades greenish; leaves mostly more than 1.5 X as long as wide, often twice as long as wide . . . . . 29 28b Petals elliptic-oblanceolate to oblanceolate broadly or narrowly so), mostly less than 4X as long as wide and cuneate, usually uniform in color; leaves mostly less than 1.5S as long as wide, often only as long as wide . . . . . . . . . . 30 29a Leaves obtuse to rarely acute, often distinctly mottled; stems glabrous; stigmas divergent-erect, the tips rarely extending between the stamens and the latter less than 1.3X taller than the pistil T. ludivicianum 29b Leaves acuminate, scarcely or obscurely mottled; stem scabrous; stigmas widely spreading, the tips often extending between the stamens, the tops often extending between the stamens and the latter often 2X taller than the pistil . T. viridescens 30a Flowers usually containing purple pigments, musk- or spice- scented (sometimes foetid); petals purple, brownish, greenish, or rarely yellow; ovary and stamens purplish . . . . . . . . .T. cuneatum 30b Flowers with no purple pigments, strongly lemon- scented; petals greenish yellow darkening to yellow; ovary and stamens greenish white . . .T. luteum