Jepson eFlora: Taxon page
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Trillium angustipetalum

Higher Taxonomy
Family: MelanthiaceaeView DescriptionDichotomous Key

Habit: Perennial herb, from rhizome or bulb, or rhizomes ending in weakly developed bulbs, scapose or not. Leaf: alternate, whorled, or mostly basal and spirally arranged, deciduous after 1 year or not. Inflorescence: raceme, panicle, or flowers 1. Flower: perianth parts 6, in 2 petal-like whorls or of sepals and petals, free or fused below, +- spreading; stamens 6, from perianth, anthers attached at base or near middle; ovary superior or partly inferior, chambers 3, styles 3, persistent. Fruit: capsule, loculicidal or septicidal.
Genera In Family: 10 genera, 130 species: northern hemisphere. Note: W North America Zigadenus moved to Toxicoscordion.
eFlora Treatment Author: Dale W. McNeal, except as noted
Scientific Editor: Dale W. McNeal, Thomas J. Rosatti.
Genus: TrilliumView DescriptionDichotomous Key

Habit: Rhizome short, thick, spreading to erect. Stem: erect, >=1 per rhizome. Leaf: 3, in 1 whorl subtending flower, sessile or subsessile, +- ovate. Inflorescence: flowers 1 per stem, erect to nodding, stalked or sessile. Flower: bisexual; sepals 3, free, persistent, +- green; petals 3, free, withering, white, +- pink, +- yellow, or purple; stamens 6; ovary chambers 3, styles 3. Fruit: capsule, +- berry-like. Seed: many, ovoid.
Species In Genus: +- 30--40 species: North America, Asia. Etymology: (Latin: 3, from leaves) Note: Trillium rivale moved to Pseudotrillium.
eFlora Treatment Author: Dale W. McNeal & Bryan D. Ness

Trillium angustipetalum (Torr.) J.D. Freeman
Stem: 2--7 dm. Leaf: subsessile, 9--25 cm, 8--15 cm wide, rounded to obtuse at tip, weakly light-brown- or dark-green-spotted. Flower: erect, sessile; odor generally musty or fetid; sepals 3.5--5.5 cm, oblong- to lance-linear; petals erect or leaning inward and +- concealing stamens, 5--11 cm, linear, dark purple; stamens 11--23 mm, tissue between anther sacs purple; ovary dark purple. Fruit: spheric, 6-angled, +- winged, fleshy. Chromosomes: n=5.
Ecology: Montane conifer forest, foothill woodland, chaparral, riparian woodland; Elevation: 30--2000 m. Bioregional Distribution: w KR, SN (exc Teh), s CCo, SCoRO; Distribution Outside California: southern Oregon. Flowering Time: Mar--Apr
Synonyms: Trillium chloropetalum (Torr.) Howell var. angustipetalum (Torr.) Munz; Trillium kurabayashii J.D. Freeman
Unabridged Note: Trillium kurabayashii treated as separate sp. in FNANM, based on differences in cytology; bract orientation, color, and texture; and petal shape.
eFlora Treatment Author: Dale W. McNeal & Bryan D. Ness
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botanical illustration including Trillium angustipetalum


Citation for this treatment: Dale W. McNeal & Bryan D. Ness 2017. Trillium angustipetalum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on September 22, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora,, accessed on September 22, 2017.

Trillium angustipetalum
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© 2015 Barry Rice
Trillium angustipetalum
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© 2011 Barry Breckling
Trillium angustipetalum
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© 2011 California Academy of Sciences
Trillium angustipetalum
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© 2010 Barry Breckling
Trillium angustipetalum
click for enlargement
© 2010 Barry Breckling
Trillium angustipetalum
click for enlargement
© 1999 California Academy of Sciences

More photos of Trillium angustipetalum in CalPhotos

Geographic subdivisions for Trillium angustipetalum:
w KR, SN (exc Teh), s CCo, SCoRO;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.