Jepson eFlora: Taxon page
Vascular Plants of California
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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 

Etymology: (Like Trillium)
Reference: Farmer 2006 Aliso 22:579--592
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
Jepson eFlora Author: Dale W. McNeal
Reference: Farmer 2006 Aliso 22:579--592
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Pseudotrillium rivale

botanical illustration including Pseudotrillium rivale

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Citation for this treatment: Dale W. McNeal 2012, Pseudotrillium rivale, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 18, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on April 18, 2024.

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

More photos of Pseudotrillium rivale
in CalPhotos

Geographic subdivisions for Pseudotrillium rivale:
1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
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).


Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).