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 2016. Trillium angustipetalum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 02, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 02, 2016.

Trillium angustipetalum
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© 2015 Barry Rice
Trillium angustipetalum
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© 2011 Barry Breckling
Trillium angustipetalum
click for enlargement
© 2011 California Academy of Sciences
Trillium angustipetalum
click for enlargement
© 2010 Barry Breckling
Trillium angustipetalum
click for enlargement
© 2015 Barry Rice
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. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

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