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

Mahonia nervosa Pursh
dull Oregon-grape (Cascade barberry)
Berberidaceae (Barberry family)

Introduction to Vascular Plants

Distribution of Mahonia nervosa
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Species Information

General:
Evergreen shrub from a rhizome; stems branched, erect, 10-60 cm tall, leafy; bark and wood yellowish.

Leaves:
Evergreen, hollylike, turning reddish in the fall, alternate, pinnate; leaflets 9-19, palmately nerved, with spiny teeth.

Flowers:
Inflorescence of clustered racemes up to 20 cm long; flowers yellow, the segments in 6's.

Fruits:
Clustered berries 8-11 mm in diameter, blue, glaucous, with a few large seeds, edible.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Yellow

Blooming Period:
Mid Spring

Fruit/Seed characteristics:
Colour: Blue
Present from Spring to Summer

Source: The USDA

Key to the Species and Taxonomic Notes

Taxonomic Key to Mahonia

1. Leaflets usually 9-19, palmately nerved.....................................M. nervosa

1. Leaflets usually 3-11, pinnately nerved

2. Leaves more than twice as long as broad, mostly with 12-29 prominent spiny teeth; leaflets 5-11; plants 0.5-4.5 m tall.......................M. aquifolium

2. Leaves less than twice as long as broad, with 15-43 inconspicuous, spiny teeth; leaflets 3-7; plant 0.1--.6 m tall.........................M. repens

Habitat / Range

Mesic to dry open slopes and open forests in the lowland, steppe and montane zones; common in SW BC, infrequent eastward in S BC; S to CA.

Source: The Illustrated Flora of British Columbia

Ecological Indicator Information

A shade-tolerant/intolerant, submontane to montane, Pacific North American evergreen shrub. Occurs in maritime to submaritime cool mesothermal climates on moderately dry to fresh, nitrogen-medium soils; its occurrence decreases with increasing precipitation, elevation, and continentality. Scatered to abundant, occasionally dominant, in the understory of semi-open forests (persists on cutover sites) on water-shedding sites. Inhabits coarse-skeletal soils. Commonly associated with Gaultheria shallon, Kindbergia oregana, and Polystichum munitum. Characteristic of mesothermal forests.

Source: Indicator Plants of Coastal British Columbia (Information applies to coastal locations only)

Climate

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 cool mesothermal.

Status Information

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
	S5 (2019)	Yellow	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer, the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Berberis nervosa Pursh
Berberis nervosa var. mendocinensis J.B. Roof
Mahonia nervosa var. mendocinensis (J.B. Roof) J.B. Roof
Odostemon nervosus (Pursh) Rydb.

Taxonomic and Nomenclatural Links

Flora North America treatment for Berberidaceae
Genetic information (NCBI Taxonomy Database)
International Plant Names Index
Taxonomic Information from the World Flora Online
Integrated Taxonomic Information System

Additional Range and Status Information Links

Burke Museum of Natural History (Washington State records)
CalFlora
Consortium of Pacific Northwest Herbaria records
Jepson Interchange
NatureServe Explorer
USDA

Additional Photo Sources

Images From CalPhoto
UT Austin's Native Plant Database
Google Image Search
Flickr Image Search

General References

Google Scholar Search
Family References
General Botanical References for BC

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2026-07-17 1:34:16 AM ]

Disclaimer: The information contained in the E-Flora atlas pages is derived from expert sources as cited in each section. This information is scientifically based. E-Flora also acts as a portal to other sites via deep links. As always, users should refer to the original sources for complete information. E-Flora BC is not responsible for the accuracy or completeness of the original information.