E-Flora BC: Electronic Atlas of the Flora of British Columbia

Ranunculus occidentalis Nutt.
Western buttercup
Ranunculaceae (Buttercup family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #20035)

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Distribution of Ranunculus occidentalis
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Species Information

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Perennial herb from a cluster of fibrous roots; stems 1 to several, erect or nearly so, 15-40 (60) cm tall, more or less hollow; plants variously hairy.
Basal broadly egg-shaped or semi-circular to kidney-shaped, the blades deeply 3-lobed or -parted, 1.5-5.5 cm long, 2-8 cm wide, the segments 1- to 2-times incised, the ultimate segments oblong or elliptic to oblanceolate or lanceolate, toothed, tips pointed to rounded, the stalks long, 1 to several times the length of blade; stem leaves alternate, more deeply dissected, shorter-stalked, transitional to the 3- to 7-parted lower bracts and entire upper bracts.
Inflorescences few- to many-flowered cymes terminal on main stem and branches; flower stalks to 10 cm long; receptacle smooth; petals 5 (6-14), distinct, yellow, oblong to narrowly egg-shaped, 5-13 mm long, 1.5-8 mm wide, nectary on upper surface, the nectary scale smooth, almost 1 mm long; sepals 5, bent back 2-3 mm from base, early deciduous, greenish or pinkish-tinged, 4-7 mm long, 2-4 mm wide, long stiff-hairy; stamens 30-60; pistils 5-20.
Achenes, several to many in a hemispheric head 3-7 mm long, 5-9 mm wide, the achenes egg-shaped, 2.6-3.6 mm long, 1.8-3 mm wide, smooth, rarely stiff-hairy, margins prominent, not keeled; beaks persistent, lanceolate- to awl-shaped, somewhat flattened, 0.4-2.2 mm long, straight or curved.
This highly variable species is often separated into numerous infraspecific taxa (Benson 1948, Scoggan 1978, Brayshaw 1989, Whittemore 1997). The treatment by Benson (1948) is unacceptable for our BC material (see Calder and Taylor 1968). It is also interesting to note that some authors fail to recognize varieties when annotating specimens (especially BC material) in major herbaria, even though they provide keys to varieties in their texts. This may be due to the fact that herbaria specimens are often intermediate between the recognized extremes.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to mesic meadows, grassy slopes, coastal bluffs, shores, clearings and open forests from the lowland to subalpine zones; common in coastal and northern BC, infrequent elsewhere; N to AK, YT and NT, E to AB and S to CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Ranunculus occidentalis

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 3 925 1980
Slope Gradient (%) 0 20 90
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
18 172 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 3 8
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: AT(1), BAFA(22), BG(1), BWBS(1), CDF(38), CMA(1), CWH(18), ESSF(30), ICH(4), IDF(2), IMA(1), MH(7), MS(4), SBPS(1), SBS(13)

Ecological Indicator Information

A shade-intolerant, submontane to subalpine, Asian and Westem North American forb distributed more in the Pacific than the Cordilleran region. Occurs on nitrogen-medium (often disturbed) soils within subalpine boreal. montane boreal, and cool mesothermal climates. Scattered to plentiful and occasionally dominant in early-seral. herbaceous (subĀ­alpine meadows) and grassy communities on water-shedding or water-receiving sites. Characteristic of disturbed sites.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References