''Mahonia nervosa'', commonly known as dwarf Oregon-grape, Cascade barberry, Cascade Oregon-grape, or dull Oregon-grape, is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

native to the northwest coast of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the C ...

from southern British Columbia south to central California, with an isolated population inland in northern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

. It is especially common in second growth,

Douglas-fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three v ...

western redcedar ''Thuja plicata'' is an evergreen coniferous tree in the cypress family Cupressaceae, native to western North America. Its common name is western redcedar (western red cedar in the UK), and it is also called Pacific redcedar, giant arborvitae, ...

forests, making use of those pools of sunlight that intermittently reach the ground. Some authors place the entire genus ''Mahonia'' within the genus ''

Berberis ''Berberis'' (), commonly known as barberry, is a large genus of deciduous and evergreen shrubs from tall, found throughout temperate and subtropical regions of the world (apart from Australia). Species diversity is greatest in South America an ...

''. The plant was collected by

Lewis Lewis may refer to: Names * Lewis (given name), including a list of people with the given name * Lewis (surname), including a list of people with the surname Music * Lewis (musician), Canadian singer * " Lewis (Mistreated)", a song by Radiohe ...

and

Clark Clark is an English language surname, ultimately derived from the Latin with historical links to England, Scotland, and Ireland ''clericus'' meaning "scribe", "secretary" or a scholar within a religious order, referring to someone who was educated ...

during their famous expedition to the West before being described for science by Frederick T. Pursh in 1813.''Fl. Amer. Sept.'' (Pursh) 219. 1814 ec. 1813 Collectors: M.Lewis, W.Clark s.n.

Description

It is an

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

with short vertical stems, mostly less than , while the leaves reach higher, rarely up to tall on exceptional sites. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

are

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struc ...

and of opposite arrangement, with 9–19 leaflets; each leaflet is strongly toothed, reminiscent of

holly ''Ilex'' (), or holly, is a genus of over 570 species of flowering plants in the family Aquifoliaceae, and the only living genus in that family. ''Ilex'' has the most species of any woody dioecious angiosperm genus. The species are evergreen o ...

, and somewhat shiny, but less so than tall Oregon-grape. The leaflets do not have a single central vein as in that species, but several veins arranged fan-like, branched from the leaflet base, hence the

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

''nervosa''. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s bloom from early to late spring and are similar to those of other Oregon-grapes, forming small yellow flowers in erect clusters up to in length. Like other species in the genus ''Mahonia,'' the

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particul ...

are dark-blue, globose berries of in diameter which occur in clusters and are tart-tasting.

Ecology

Low Oregon-grape thrives in sun or shade and is a common or dominant species throughout the understories in montane, sub-montane, and mixed evergreen forests in the Pacific Northwest. It reaches greatest abundance on relatively dry and warm sites, but occurs in fairly moist environments as well. It grows in a variety of soil types. It is restricted to lower elevations, from sea level to . ''Mahonia nervosa'' can complete its life cycle even in the deep shade of dense hemlock-

forests, so it is a

climax species Climax species, also called late seral, late-successional, K-selected or equilibrium species, are plant species that can germinate and grow with limited resources; e.g., they need heat exposure or low water availability. They are the species w ...

in old-growth forests where it is often dominant. It also occurs in disturbed sites, usually reaching peak abundance from 4 to 10 years after fire or clearcutting. The plant can reproduce via seeds or by vegetative means, sprouting from

rhizome In botany and dendrology, a rhizome (; , ) is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow ho ...

s which extend laterally through the soil. Its foliage is browsed by

black-tailed deer Two forms of black-tailed deer or blacktail deer that occupy coastal woodlands in the Pacific Northwest of North America are subspecies of the mule deer (''Odocoileus hemionus''). They have sometimes been treated as a species, but virtually all ...

and

Roosevelt elk The Roosevelt elk (''Cervus canadensis roosevelti)'', also known commonly as the Olympic elk and Roosevelt's wapiti, is the largest of the four surviving subspecies of elk (''Cervus canadensis'') in North America by body mass (although by antl ...

in some areas, but is ignored in others. Various small mammals feed on the foliage extensively, and it is extremely important food source for the

white-footed vole The white-footed vole (''Arborimus albipes'') is a species of rodent in the family Cricetidae. It is found only in the United States. Its natural habitat is temperate forest A forest is an area of land dominated by trees. Hundreds of def ...

in the Coast Range of Oregon. The fruits are eaten by small birds and mammals, and by black-tailed deer in some areas. The nectar of the genus ''Mahonia'' is favored by the

Anna's hummingbird Anna's hummingbird (''Calypte anna'') is a medium-sized bird species of the family Trochilidae. It was named after Anna Masséna, Duchess of Rivoli. It is native to western coastal regions of North America. In the early 20th century, Anna's hu ...

Uses

Some Plateau Indian tribes drank an infusion of the root to treat

rheumatism Rheumatism or rheumatic disorders are conditions causing chronic, often intermittent pain affecting the joints or connective tissue. Rheumatism does not designate any specific disorder, but covers at least 200 different conditions, including art ...

. Modern medicine uses it against parasites, bacteria, viruses, diabetes, and high cholesterol. The

Yana people The Yana were a group of Native Americans indigenous to Northern California in the central Sierra Nevada, on the western side of the range. Their lands, prior to encroachment by white settlers, bordered the Pit and Feather rivers. They were ...

dried and ground the fruits to make a

mush In multiplayer online games, a MUSH (a backronymed variation on MUD most often expanded as Multi-User Shared Hallucination, though Multi-User Shared Hack, Habitat, and Holodeck are also observed) is a text-based online social medium to which mult ...

. They can also be dried and eaten like raisins, or used for jelly. The inner bark is colored yellow by the alkaloid berberine, and was used as a dye by native groups. The leaves are often used in floral arrangements.

References

External links

Flora of North America (as ''Berberis nervosa'')Jepson Flora Project (as ''Berberis nervosa'')
{{Taxonbar, from=Q647429 nervosa Flora of the Northwestern United States Flora of British Columbia Flora of California Flora of the Klamath Mountains Natural history of the California Coast Ranges Plants described in 1813 Plants used in traditional Native American medicine Garden plants of North America Bird food plants Flora without expected TNC conservation status