View source for Trillium

{{Treatment/ID
|accepted_name=Trillium
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 339. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 158. 1754
|year=1754
}}
|common_names=Trille
|basionyms=
|synonyms=
|hierarchy=Liliaceae;Trillium
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Liliaceae]]</div><div class="higher-taxon"><small>genus</small>[[Trillium]]</div></div>
|etymology=Latin, trilix, triple, alluding to the flowers having parts in threes
|volume=Volume 26
|mention_page=page 51, 54, 56, 91, 97, 101, 110, 113, 150
|treatment_page=page 90
}}<!--

--><span class="statement" id="st-d0_s0" data-properties="whole_organism duration;whole_organism architecture;whole_organism architecture;whole_organism growth form"><b>Herbs,</b> perennial, scapose, rhizomatous;</span> <span class="statement" id="st-d0_s1" data-properties="rhizome location;rhizome orientation;rhizome orientation;rhizome architecture;rhizome architecture;rhizome architecture;rhizome length;rhizome width;rhizome texture;rhizome length;distal end shape;apex shape;terminal bud size;terminal cataphyll size;terminal cataphyll quantity;terminal root size;terminal root quantity;terminal root architecture;terminal root derivation;terminal root relief">rhizomes subterranean, horizontal or semierect, monopodial, unbranched or weakly branched, elongated to thick and fleshy, compressed-shortened, distal end tapered to point or praemorse, apex bearing large terminal bud, numerous cataphylls, and contractile, adventitious, ringed roots.</span> <span class="statement" id="st-d0_s2" data-properties="scape orientation;scape location;scape orientation;scape course;cataphyll arrangement"><b>Scapes </b>arising from terminal bud or axil of adjacent cataphylls, aerial (subterranean in T. petiolatum), erect, straight (decumbent, S-shaped in T. decumbens and T. reliquum).</span> <span class="statement" id="st-d0_s3" data-properties="bract coloration;bract coloration;bract architecture;bract architecture;bract architecture;bract architecture or coloration or relief;bract shape;plant life cycle;whorl quantity;vein quantity;vein size"><b>Bracts </b>on mature plants in whorl of 3, uniformly green or mottled, foliaceous, petiolate or sessile, venation palmate-reticulate, with 3–5 major veins, ovate or obovate to elliptical.</span> <span class="statement" id="st-d0_s4" data-properties="inflorescence position or structure subtype;inflorescence architecture"><b>Inflorescences </b>terminal, 1-flowered.</span> <span class="statement" id="st-d0_s5" data-properties="flower architecture;flower architecture;flower architecture"><b>Flowers:</b> some totally to partially syncarpous, pedicellate or sessile;</span> <span class="statement" id="st-d0_s6" data-properties="sepal duration;sepal quantity;sepal fusion;sepal coloration;sepal coloration;sepal architecture;sepal shape;sepal shape;sepal shape;sepal shape;sepal shape;sepal arrangement;marking coloration">sepals persistent, 3, distinct, green, maroon, or with maroon markings, foliaceous, oblong, ovate, or lanceolate, alternating with bracts;</span> <span class="statement" id="st-d0_s7" data-properties="petal quantity;petal orientation;petal orientation;petal orientation;petal orientation;petal orientation;petal fusion;petal coloration;petal coloration or density;petal coloration;petal coloration;petal coloration;petal coloration;petal shape;petal shape">petals shriveling after anthesis, typically 3, erect, spreading, or recurved, distinct, red, purple, pink, white, yellow, green, or combination of these, ovate or obovate to linear, sometimes clawed;</span> <span class="statement" id="st-d0_s8" data-properties="stamen quantity;stamen arrangement;stamen orientation;stamen orientation;stamen arrangement;whorl quantity;whorl quantity">stamens 6, alternating in 2 whorls of 3, erect, incurved, or divergent;</span> <span class="statement" id="st-d0_s9" data-properties="filament height or length or size;filament size">filaments mostly short, basally expanded;</span> <span class="statement" id="st-d0_s10" data-properties="anther architecture or structure in adjective form;anther variability;anther length or size;anther dehiscence;anther dehiscence;anther dehiscence;anther dehiscence;anther dehiscence;anther dehiscence">anthers 2-locular, ± equaling or longer than filaments, dehiscence extrorse, latrorse, or introrse;</span> <span class="statement" id="st-d0_s11" data-properties="connectif prominence or shape">connectives flat between (or in some species extending beyond) anther sacs;</span> <span class="statement" id="st-d0_s12" data-properties="ovary position;proximal portion architecture or structure in adjective form;proximal portion shape;proximal portion shape;proximal portion arrangement;proximal portion arrangement">ovary superior, proximal portion 3-locular, 3-lobed or 6-lobed, some axile, some parietal or a combination of both, distal portion forming stigmas;</span> <span class="statement" id="st-d0_s13" data-properties="stigma duration;stigma quantity;stigma orientation;stigma architecture;stigma orientation;stigma fusion;stigma architecture;stigma architecture;stigma shape;style height or length or size">stigmas often persistent, 3, spreading, twisted, or erect, sometimes connate, sessile or with very short style, linear to subulate.</span> <span class="statement" id="st-d0_s14" data-properties="fruit architecture;fruit architecture;fruit texture;fruit dehiscence;suture prominence;cell architecture"><b>Fruits </b>capsular or baccate, fleshy with obscure sutures, not or rarely dehiscent along sutures, each shed as unit through abscission of thin-walled cells at base.</span> <span class="statement" id="st-d0_s15" data-properties="elaiosome coloration;elaiosome coloration;elaiosome size;elaiosome coating;elaiosome reproduction"><b>Seeds </b>many, elliptic, 2–4 mm, bearing white or yellowish, large, oily, myrmecochorous elaiosome (aril).</span> <span class="statement" id="st-d0_s16" data-properties="seed quantity;seed arrangement or shape;seed some measurement;x=5 . 2n chromosome quantity;x=5 . 2n chromosome quantity">x = 5.2n = 10 in all American species recorded.</span><!--

-->{{Treatment/Body
|distribution=North America;Asia
|discussion=<p>Species 43 (38 in the flora).</p><!--
--><p>Trillium is traditionally divided into two subgenera, which overlap in some characters. Botanists consider subg. Trillium to be the more primitive group, because the genera considered closest to Trillium all have pedicellate flowers, as does subg. Trillium, except for one variety of T. pusillum that bears sessile to only barely pedicillate flowers.</p><!--
--><p>There is not yet agreement among taxonomists about the relationships among the species within the genus. Certain ones, such as Trillium recurvatum and T. lancifolium, clearly are closely related, but the interrelationships of many others are not obvious. In the absence of definitive studies, the species are listed here alphabetically within subgenera.</p><!--
--><p>Several species of Trillium contain sapogenins that have been used medicinally as astringents, coagulants, expectorants, and uterine stimulants, hence the common names birthwort and Indian balm, and T. erectum, T. grandiflorum, and possibly other species have been utilized commercially as beth root (W. B. Zomlefer 1996). Fruits, seeds, and rhizomes of trilliums are generally considered to be poisonous. Deer, however, feed voraciously on T. grandiflorum plants, especially in early spring.</p><!--
--><p>Gardeners and wildflower enthusiasts, over most of the temperate zones of the world, consider trilliums to be among the most beautiful of wildflowers.</p><!--
--><p>Species of Trillium exhibit few and obscure structural differences, making key construction difficult (J. D. Freeman 1975). The key below, adapted with permission from F. W. Case and R. B. Case (1997), works best with fresh, live material. Many species hybridize, especially within the T. erectum group. Hybrids and the occasional anomalous, odd-sized, or diseased individuals are not keyed here.</p><!--
--><p>Morphologically, Trillium plants produce no true leaves or stems above ground. The horizontal rhizome produces dry, scalelike leaves (cataphylls). The above-ground plant is a flowering scape, and technically the leaflike structures are bracts subtending the flower. Origin aside, the bracts function in photosynthesis and have external and internal structure similar to that of a leaf, and many authors refer to them as leaves.</p>
|tables=
|references=
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Flower pedicellate; bract blades usually not mottled.
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Flower sessile, bract blades usually mottled (except in T. pusillum).
|[[#key-0-19| > 19]]
|-id=key-0-2
|2
|Stigmas ± connate at least basally, or closely grouped and uniform, of uniform thickness throughout.
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Stigmas distinct, often basally thickened or subulate.
|[[#key-0-11| > 11]]
|-id=key-0-3
|3
|Scapes usually 0.4–2 dm at anthesis.
|[[#key-0-4| > 4]]
|-id=key-0-3
|3
|Scapes usually 2.0–4.5 dm at anthesis.
|[[#key-0-7| > 7]]
|-id=key-0-4
|4
|Bract blade bluish green, apex round-obtuse; scapes 6-gonal in cross section.
|[[Trillium nivale|Trillium nivale]]
|-id=key-0-4
|4
|Bract blade green, often with maroon undertones early, apex acuminate, blunt-acute, or rounded; scapes round in cross section.
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Pedicel recurved below bracts at anthesis, or rarely leaning to ± horizontal distal to bracts; petals strongly arcuate-recurved from base, white, pink, or rose.
|[[Trillium catesbaei|Trillium catesbaei]]
|-id=key-0-5
|5
|Pedicel ± erect at anthesis; petals erect-spreading to widely spreading, not recurved or recurved only in distal 1/2, white or white with madder purple flecks.
|[[#key-0-6| > 6]]
|-id=key-0-6
|6
|Bracts strongly petiolate, blade apex long-acuminate, weakly to strongly cordate basally, glossy, bluish green, sometimes with lighter silvery green pattern on or near main veins; sepals shorter and narrower than petals, apex rounded-apiculate; petals erect-spreading, ovate-cordate to ± orbicular, widest at or beyond middle, round-tapered distal to middle to apiculate-acuminate tip, margins mostly without undulations, white, usually sparsely to very heavily flecked with madder-purple, color not changing with age; Siskiyou Mountains of n California and Oregon.
|[[Trillium rivale|Trillium rivale]]
|-id=key-0-6
|6
|Bracts very short-petiolate, subsessile, or sessile, blade apex obtuse, not glossy, green with maroon undertones; sepals about as large and prominent as petals, apex round to blunt; petals spreading-ascending, weakly recurved in distal 1/2, oblong to narrowly lanceolate, widest in proximal 1/3, margins strongly undulate, white, aging to deep rose abaxially; e U.S.
|[[Trillium pusillum|Trillium pusillum]]
|-id=key-0-7
|7
|Stigmas connate into style 2–6 mm; bract blades elliptic-ovate, ovate-lanceolate to lanceolate, usually 1.5–8 cm wide.
|[[#key-0-8| > 8]]
|-id=key-0-7
|7
|Stigmas barely connate basally, rarely completely distinct; bract blade ovate to rhombic, usually 8–20 cm wide.
|[[#key-0-9| > 9]]
|-id=key-0-8
|8
|Pedicel erect or only slightly leaning; petals erect to widely spreading, linear to narrowly elliptic, white at anthesis, darkening with age to light to medium deep pink, with inverted V-shaped, white base; bracts horizontal to drooping distally, blade lanceolate to lanceolate-ovate; stamens straight.
|[[Trillium persistens|Trillium persistens]]
|-id=key-0-8
|8
|Pedicel leaning to almost horizontal or clearly recurved and declined; petals arcuate-recurved, oblong-lanceolate, white, pink, or rose, darkening to pink or nonfading with age; bracts and their margins often slightly raised, exposing flowers at anthesis, blade elliptic-ovate; stamens recurved.
|[[Trillium catesbaei|Trillium catesbaei]]
|-id=key-0-9
|9
|Petals with distinct, dark red, inverted V-shaped mark basally; bracts strongly petiolate; ovary 3-lobed or -angled
|[[Trillium undulatum|Trillium undulatum]]
|-id=key-0-9
|9
|Petals uniformly white or pink, or with faint pink blush, no distinct, V-shaped marking; bracts subsessile, sessile, or short-petiolate; ovary 6-lobed or -angled.
|[[#key-0-10| > 10]]
|-id=key-0-10
|10
|Petals erect basally, flaring and recurving above middle, margins undulate-wavy, overlapping basally, rolled, forming tube that conceals ovary when viewed from above, obovate to lanceolate, rarely suborbicular, 4–7.5 × 2–4 cm, white or rarely pink, aging to pink-purple; e North America.
|[[Trillium grandiflorum|Trillium grandiflorum]]
|-id=key-0-10
|10
|Petals erect-ascending, widely spreading in distal 1/2, distal margins usually flat to weakly undulate to undulate, scarcely touching basally to overlapping and forming tube, not concealing ovary when viewed from above, linear to obovate, 1.5–7 × 1–4 cm, white, often with pink or blush markings, aging to deep rosy pink, purple, or dark red; w North America.
|[[Trillium ovatum|Trillium ovatum]]
|-id=key-0-11
|11
|Stigmas short, 2–4 mm, uniformly thick, recurved and appearing ± lobed adaxially, at least in dried specimens; bracts strongly petiolate, blade ovate-lanceolate, mostly less than 6 cm wide, weakly to strongly cordate basally.
|[[Trillium rivale|Trillium rivale]]
|-id=key-0-11
|11
|Stigmas of various lengths, basally thickened, gradually tapered, erect distally, reflexed, or coiled, not lobed adaxially; bracts sessile to subsessile, blade elliptic, obovate, or rhombic, mostly more than 6 cm wide, gradually tapered, rounded or weakly cuneate basally.
|[[#key-0-12| > 12]]
|-id=key-0-12
|12
|Anthers ± equaling filaments, pale lavender-pink or -gray; petals oblong-lanceolate, recurved-reflexed from just above base, extending behind plane of sepal bases for more than 1/2 their length, white or rarely pale pink, thin-textured, adaxial veins inconspicuous.
|[[Trillium cernuum|Trillium cernuum]]
|-id=key-0-12
|12
|Anthers longer or shorter than, rarely equaling filaments, white, creamy white, yellow, purple, or maroon; petals ovate to obovate, spreading, flat, or, if recurved, in distal 1/2 only, red, maroon purple, rose, cream, or white, more rarely pale yellow, rarely 2-colored, heavy- or fleshy-textured, adaxial veins conspicuous, appearing engraved.
|[[#key-0-13| > 13]]
|-id=key-0-13
|13
|Ovary greenish white or white, occasionally with reddish purple stains at apex.
|[[#key-0-14| > 14]]
|-id=key-0-13
|13
|Ovary dark purple or maroon.
|[[#key-0-15| > 15]]
|-id=key-0-14
|14
|Pedicel strongly recurved beneath bracts; anthers thin, dark purple; petals ovate-elliptic, white, rarely 2-colored rose and white, apex acuminate; stigmas shorter than ovary; rhizome tapered to point distally.
|[[Trillium rugelii|Trillium rugelii]]
|-id=key-0-14
|14
|Pedicel erect, declined, or recurved; anthers thick, creamy white or yellow; petals ovate-lanceolate to broadly ovate, creamy white, not 2-colored, apex acute; stigmas ± equaling ovary; rhizome praemorse.
|[[Trillium flexipes|Trillium flexipes]]
|-id=key-0-15
|15
|Pedicel recurved or declined; flower held proximal to or below bracts.
|[[#key-0-16| > 16]]
|-id=key-0-15
|15
|Pedicel erect, or leaning from base, not recurved or declined; flower erect or dangling but not distinctly below bracts.
|[[#key-0-17| > 17]]
|-id=key-0-16
|16
|Pedicel declined, ± straight; stamens 1.5–2 times taller than small, ± globose to conical-pyramidal ovary; anthers maroon to grayish purple; petals 3–6.5 × 4–6 cm, usually maroon to brownish red, ovate-suborbicular, spreading to weakly recurved, longer than sepals.
|[[Trillium vaseyi|Trillium vaseyi]]
|-id=key-0-16
|16
|Pedicel recurved beneath bracts; stamens ± equaling or not more than 1/3 longer than prominent, flask-shaped ovary; anthers dark purple; petals 2.5–5 × 0.8–3.5 cm, usually white or 2-colored, distally white, ovate to broadly ovate, recurved, ± equaling sepals
|[[Trillium rugelii|Trillium rugelii]]
|-id=key-0-17
|17
|Perianth open, usually flat; petals carried in ± same plane as sepals, or ascending slightly, spreading, not recurved, lanceolate to ovate, to 2+ times width of sepals; sepals flat to somewhat sulcate apically; flower odor fetid, of wet dog.
|[[Trillium erectum|Trillium erectum]]
|-id=key-0-17
|17
|Perianth gaping, strongly 3-dimensional; petals erect-spreading or recurved in distal 1/2, ovate to ovate-orbicular, wider than sepals; sepal apex sulcate; flower odor musty or fruity.
|[[#key-0-18| > 18]]
|-id=key-0-18
|18
|Petals creamy white, 1.5 times sepal length, 4–7 × 1.5–4 cm, not recurved to weakly so at tip; pedicel not strongly reflexed, flowers facing ± upward, odor sweet, applelike; sepal apex mildly sulcate.
|[[Trillium simile|Trillium simile]]
|-id=key-0-18
|18
|Petals dark reddish maroon to purplish, less than 1.5 times sepal length, 1.8–5 × 1–3 cm, often recurved in distal 1/2; pedicel reflexed at tip; flowers facing outward at ± right angle to pedicel, odor funguslike; sepal apex strongly sulcate.
|[[Trillium sulcatum|Trillium sulcatum]]
|-id=key-0-19
|19
|Stigmas connate basally into short style, threadlike, tips widely spreading; petals spreading from base with distal 1/2 flat or weakly ascending, exposing stamens and ovary, of short duration, margins undulate
|[[Trillium pusillum|Trillium pusillum]]
|-id=key-0-19
|19
|Stigmas distinct, erect, subulate with tips divergent-recurved, or linear and usually slightly thickened basally with tips recoiled; petals mostly erect from base, ± connivent, often at least partially concealing stamens and ovary, or erect-spreading, tips incurving slightly, long-lasting, sometimes spiral-twisted, margins entire.
|[[#key-0-20| > 20]]
|-id=key-0-20
|20
|Scapes decumbent or semidecumbent, or subterranean; bracts resting near or on ground, or with petioles arising from scape apex at or near ground surface.
|[[#key-0-21| > 21]]
|-id=key-0-20
|20
|Scapes erect, straight; bracts held well above ground, or bract tips touching ground only in early anthesis.
|[[#key-0-23| > 23]]
|-id=key-0-21
|21
|Scapes ± erect, largely subterranean; bracts long-petiolate, blade not mottled; individual bracts Plantago-like; w United States.
|[[Trillium petiolatum|Trillium petiolatum]]
|-id=key-0-21
|21
|Scapes decumbent or semidecumbent, S-shaped, aerial; bracts sessile or only short-petiolate, blade heavily mottled; se United States.
|[[#key-0-22| > 22]]
|-id=key-0-22
|22
|Anther dehiscence extrorse; scapes distinctly puberulent especially just below bracts; petals linear-lanceolate or oblanceolate, 4–8 cm or more; filaments 2–5 mm.
|[[Trillium decumbens|Trillium decumbens]]
|-id=key-0-22
|22
|Anther dehiscence introrse; scapes glabrous; petals narrowly elliptic-oblanceolate, 2.5–5.5 cm; filaments 1–2 mm.
|[[Trillium reliquum|Trillium reliquum]]
|-id=key-0-23
|23
|Sepals strongly reflexed at bases, often below bracts and parallel to scape, or adpressed to bracts; anther connectives strongly curved inward; rhizomes horizontal, elongated, slender, very brittle, white.
|[[#key-0-24| > 24]]
|-id=key-0-23
|23
|Sepals not strongly reflexed, spreading or somewhat erect; anther connectives straight; rhizomes horizontal or erect, thick or somewhat compressed-thickened and superficially bulblike, not brittle, brownish.
|[[#key-0-25| > 25]]
|-id=key-0-24
|24
|Petals lanceolate-ovate, base attenuate to weakly clawed, ca. 2 times longer than wide; bracts petiolate.
|[[Trillium recurvatum|Trillium recurvatum]]
|-id=key-0-24
|24
|Petals linear to narrowly spatulate, clawed, at least 4 times longer than wide; bracts sessile.
|[[Trillium lancifolium|Trillium lancifolium]]
|-id=key-0-25
|25
|Petals white, rarely tinged pale pink or purplish near bases.
|[[#key-0-26| > 26]]
|-id=key-0-25
|25
|Petals maroon, reddish brown, bronze, yellow, or green.
|[[#key-0-28| > 28]]
|-id=key-0-26
|26
|Anther dehiscence introrse; ovary purple.
|[[Trillium chloropetalum|Trillium chloropetalum]]
|-id=key-0-26
|26
|Anther dehiscence latrorse; ovary green or greenish white, rarely purple at base.
|[[#key-0-27| > 27]]
|-id=key-0-27
|27
|Scapes usually 2.2–5.8 dm; petals oblanceolate to obovate, 4.8–8 cm, white to creamy white, rarely very pale pink or pinkish basally.
|[[Trillium albidum|Trillium albidum]]
|-id=key-0-27
|27
|Scapes usually 1.7–3 dm; petals linear to linear-lanceolate, 2.2–4.5 cm, white, rarely purplish basally.
|[[Trillium parviflorum|Trillium parviflorum]]
|-id=key-0-28
|28
|Petals yellow, pale yellow, greenish, or bicolored green with purplish base.
|[[#key-0-29| > 29]]
|-id=key-0-28
|28
|Petals usually maroon, reddish brown, pink, greenish maroon, purplish bronze, white, or brown throughout (except in pigment-free mutant individuals with petals pale green or yellowish green); occasionally yellow in T. cuneatum, T. chloropetalum, T. gracile, T. maculatum, and T. foetidissimum, occasionally 2-colored in T. ludovicianum.
|[[#key-0-33| > 33]]
|-id=key-0-29
|29
|Petal bases not clawed.
|[[#key-0-30| > 30]]
|-id=key-0-29
|29
|Petal bases weakly to strongly clawed.
|[[#key-0-31| > 31]]
|-id=key-0-30
|30
|Petals oblanceolate to lanceolate, apex long-acuminate; stamens 11–18 mm; anther connective extending 0.5 mm or less beyond sacs; stamens slightly longer than or ± equaling pistil; flower odor strongly of lemon; se United States.
|[[Trillium luteum|Trillium luteum]]
|-id=key-0-30
|30
|Petals oblanceolate to obovate, apex variably acute to almost truncate; stamens 17–26 mm; anther connective extending 1–1.5 mm beyond sacs; stamens ca. 2 times as long as pistil; flower odor spicy, of rose; California.
|[[Trillium chloropetalum|Trillium chloropetalum]]
|-id=key-0-31
|31
|Petals widely spatulate, pale sulfur-yellow fading to ± cream, with broadly cuneate basal claw, claw green, sometimes obscurely marked with purple; apex apiculate, nipplelike in at least 1 petal.
|[[Trillium discolor|Trillium discolor]]
|-id=key-0-31
|31
|Petals narrowly spatulate to linear-spatulate, green, bicolored, green with purplish base, rarely all purple, obscurely to clearly narrow-clawed basally, claw purple or green; apex round-acute to obtuse, lacking nipple.
|[[#key-0-32| > 32]]
|-id=key-0-32
|32
|Bract (under magnification) with numerous stomates across entire adaxial surface; pistil 2/3 stamens; anther dehiscence introrse-latrorse; petals green or yellowish green distal to weak purplish claw (very rarely purplish green throughout); flower odor of rotten fruit.
|[[Trillium viride|Trillium viride]]
|-id=key-0-32
|32
|Bract adaxially without stomates or with stomates near apex only; pistil 1/2 stamens; anther dehiscence latrorse; petals green or yellowish green distal to distinct purplish claw (rarely, petal purple throughout); flower odor spicy or musty.
|[[Trillium viridescens|Trillium viridescens]]
|-id=key-0-33
|33
|Anther dehiscence extrorse; stamens not obscured by petals; petals horizontal, with 1–2 spiral twists.
|[[Trillium stamineum|Trillium stamineum]]
|-id=key-0-33
|33
|Anther dehiscence introrse or latrorse; stamens at least partially obscured by petals; petals erect to divergent and slightly spreading with tips ± incurved, not spirally twisted.
|[[#key-0-34| > 34]]
|-id=key-0-34
|34
|Anther dehiscence latrorse, occasionally introrse basally with age.
|[[#key-0-35| > 35]]
|-id=key-0-34
|34
|Anther dehiscence introrse.
|[[#key-0-38| > 38]]
|-id=key-0-35
|35
|Anther connectives extended 1–2 mm beyond sacs; margins of distal 1/3 of bract blade straight to apex.
|[[#key-0-36| > 36]]
|-id=key-0-35
|35
|Anther connectives extended scarcely if at all to 0.5 mm beyond sacs; margins of distal 1/3 of bract blade convex-curved to apex.
|[[#key-0-37| > 37]]
|-id=key-0-36
|36
|Scape 1.5 times longer than bracts; bract tips at anthesis often touching ground; petals 3–4 times longer than wide.
|[[Trillium underwoodii|Trillium underwoodii]]
|-id=key-0-36
|36
|Scape 2.5–3 times longer than bracts; bract tips at anthesis held well away from ground; petals ca. 2 times longer than wide.
|[[Trillium decipiens|Trillium decipiens]]
|-id=key-0-37
|37
|Petals 0.9–2.7 cm wide, oblanceolate to elliptic-obovate, narrowed to cuneate but not clawed base, erect.
|[[Trillium cuneatum|Trillium cuneatum]]
|-id=key-0-37
|37
|Petals 0.4–0.8 cm wide, linear-oblanceolate, weakly clawed basally, erect-spreading.
|[[Trillium ludovicianum|Trillium ludovicianum]]
|-id=key-0-38
|38
|Stamens ca. 2 times as long as pistil.
|[[#key-0-39| > 39]]
|-id=key-0-38
|38
|Stamens equaling, less than, or very slightly longer than pistil.
|[[#key-0-40| > 40]]
|-id=key-0-39
|39
|Petals oblanceolate to obovate, 6.5–10 × 1.5–2.5 cm; anther connective extended 1–1.5 mm beyond sacs; California.
|[[Trillium chloropetalum|Trillium chloropetalum]]
|-id=key-0-39
|39
|Petals linear-elliptic to oblanceolate, 2–4 × 0.3–0.8 cm; anther connective extended 0.1–1 mm beyond sacs; e Texas and w Louisiana.
|[[Trillium gracile|Trillium gracile]]
|-id=key-0-40
|40
|Anther connective not extended beyond sac, or, if extended, rarely to 0.5–1 mm.
|[[#key-0-41| > 41]]
|-id=key-0-40
|40
|Anther connective extended 1 mm or more beyond sac.
|[[#key-0-42| > 42]]
|-id=key-0-41
|41
|Scape 1.4–4 dm; bracts 7–15 × 4.6–6.7 cm; petals narrowly oblanceolate-spatulate to linear-spatulate, spreading-erect, becoming connivent-erect with age, 4–7 × 0.7–1.7 cm, clear dark red-maroon, reddish purple, or rarely yellow above purplish base or clear sulfur yellow, distal margins upraised from about widest point to near petal base; stigmas 2–4 mm; se United States.
|[[Trillium maculatum|Trillium maculatum]]
|-id=key-0-41
|41
|Scape 2.5–5.5 dm; bracts 11–18 × 12–17 cm; petals oblanceolate, spreading-erect, 5.5–11 × 2–3.5 cm, glossy dark maroon-red or purple, margins ± flat, widest at or below middle, cuneate basally; stigmas 6–8 mm; n California and extreme sw Oregon.
|[[Trillium kurabayashii|Trillium kurabayashii]]
|-id=key-0-42
|42
|Anther connective extended 2–5+ mm beyond sac.
|[[Trillium sessile|Trillium sessile]]
|-id=key-0-42
|42
|Anther connective extended ca. 1–1.5 mm beyond sac.
|[[#key-0-43| > 43]]
|-id=key-0-43
|43
|Scapes 2.5–6 dm; petals linear, erect, 5–10 cm, 8–10 times longer than wide, glossy, dark purple to red-purple, inrolling with age; bract blades 10–22 × 8.7–15 cm, obscurely and sparsely or not at all mottled or spotted darker greenish brown, subsessile; c, s California.
|[[Trillium angustipetalum|Trillium angustipetalum]]
|-id=key-0-43
|43
|Scapes 0.8–2.8 dm; petals narrowly elliptic to linear-lanceolate, weakly incurved, 2–5 × 0.3–0.5 cm, not glossy, pinkish purple, light to dark reddish or brownish purple, rarely yellow, not inrolling with age; bract blades 6.7–12 × 3.8–6 cm, strongly mottled, sessile; e Louisiana, sw Mississippi.
|[[Trillium foetidissimum|Trillium foetidissimum]]
|}
</div></div><!--

-->{{#Taxon:
name=Trillium
|author=Frederick W. Case Jr.
|authority=Linnaeus
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Liliaceae
|distribution=North America;Asia
|reference=None
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=1753;1754
|special status=
|source xml=https://bibilujan@bitbucket.org/aafc-mbb/fna-fine-grained-xml.git/src/84153f6d59a0a91d69695978a64cee7560374f8e/V26/V26_95.xml
|genus=Trillium
|anther architecture or structure in adjective form=2-locular
|anther dehiscence=introrse;latrorse;introrse;latrorse;extrorse;dehiscence
|anther length or size=more or less equaling or longer
|anther variability=equaling
|apex shape=praemorse
|bract architecture=sessile;petiolate;foliaceous
|bract architecture or coloration or relief=palmate-reticulate
|bract coloration=mottled;green
|bract shape=obovate;elliptical
|cataphyll arrangement=adjacent
|cell architecture=thin-walled
|connectif prominence or shape=flat
|distal end shape=tapered
|elaiosome coating=oily
|elaiosome coloration=yellowish;white
|elaiosome reproduction=myrmecochorous
|elaiosome size=large
|filament height or length or size=short
|filament size=expanded
|flower architecture=sessile;pedicellate;syncarpous
|fruit architecture=baccate;capsular
|fruit dehiscence=dehiscent
|fruit texture=fleshy
|inflorescence architecture=1-flowered
|inflorescence position or structure subtype=terminal
|marking coloration=maroon
|ovary position=superior
|petal coloration=green;yellow;white;pink;red
|petal coloration or density=purple
|petal fusion=distinct
|petal orientation=recurved;spreading;recurved;spreading;erect
|petal quantity=3
|petal shape=clawed;obovate;linear
|plant life cycle=mature
|proximal portion architecture or structure in adjective form=3-locular
|proximal portion arrangement=parietal;axile
|proximal portion shape=6-lobed;3-lobed
|rhizome architecture=branched;unbranched;monopodial
|rhizome length=compressed-shortened;elongated
|rhizome location=subterranean
|rhizome orientation=semierect;horizontal
|rhizome texture=fleshy
|rhizome width=thick
|scape course=straight
|scape location=aerial
|scape orientation=erect;arising
|seed arrangement or shape=elliptic
|seed quantity=many
|seed some measurement=2mm;4mm
|sepal architecture=foliaceous
|sepal arrangement=alternating
|sepal coloration=maroon;green
|sepal duration=persistent
|sepal fusion=distinct
|sepal quantity=3
|sepal shape=lanceolate;ovate;lanceolate;ovate;oblong
|stamen arrangement=divergent;alternating
|stamen orientation=incurved;erect
|stamen quantity=6
|stigma architecture=with very short style;sessile;twisted
|stigma duration=persistent
|stigma fusion=connate
|stigma orientation=erect;spreading
|stigma quantity=3
|stigma shape=linear;subulate
|style height or length or size=short
|suture prominence=obscure
|terminal bud size=large
|terminal cataphyll quantity=numerous
|terminal cataphyll size=large
|terminal root architecture=contractile
|terminal root derivation=adventitious
|terminal root quantity=numerous
|terminal root relief=ringed
|terminal root size=large
|vein quantity=3;5
|vein size=major
|whole_organism architecture=rhizomatous;scapose
|whole_organism duration=perennial
|whole_organism growth form=herb
|whorl quantity=3;2;3
|x=5 . 2n chromosome quantity=10;10
}}<!--

-->[[Category:Treatment]][[Category:Liliaceae]]