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Pseudotrillium rivale

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: PseudotrilliumView Description 

Species In Genus: 1 sp.: California, Oregon. Etymology: (Like Trillium)

Pseudotrillium rivale (S. Watson) S.B. Farmer
Stem: 0.5--2 dm. Leaf: 3, in 1 whorl subtending flower, petioled (subsessile), blade 1.7--11 cm, lanceolate to cordate, acute to acuminate, leathery. Inflorescence: flowers 1 per stem; peduncle generally erect as flower opens, becoming recurved and continuing to elongate below bracts after pollination until ovary contacts soil. Flower: bisexual; sepals 1--2 cm, 4--11 mm wide, lanceolate or ovate to oblong; petals 1.5--3 cm, 0.8--1.9 cm wide, ovate-cordate, white (pink), generally purple-spotted; stamens 6, 6--15 mm; ovary chambers 3 stigmas 3, recurved. Fruit: capsule, berry-like, +- pulpy, rarely dehiscent, generally shed as a unit. Chromosomes: n=5.
Ecology: Yellow-pine forest along rocky streambanks and in Darlingtonia bogs, generally serpentine; Elevation: 40--1500 m. Bioregional Distribution: KR; Distribution Outside California: southwestern Oregon. Flowering Time: Apr--Jun
Synonyms: Trillium rivale S. Watson
eFlora Treatment Author: Dale W. McNeal
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botanical illustration including Pseudotrillium rivale


Citation for this treatment: Dale W. McNeal 2016. Pseudotrillium rivale, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on April 28, 2016.

Pseudotrillium rivale
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© 2007 Steve Matson
Pseudotrillium rivale
click for enlargement
© 2007 Steve Matson

More photos of Pseudotrillium rivale in CalPhotos

Geographic subdivisions for Pseudotrillium rivale:
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.