synonym – Frangula purshiana

purshiana – refers to Frederick T. Pursh (1774–1820), a German/U.S. botanist and important North American plant collector

Native range: Western North America

Leaves:

• alternate (may seem almost opposite on new growth)
• simple, clustered near ends of branches
• 2–6” long
• elliptic to obtuse
• prominent pinnate venation in furrows, the surface washboard-y (raised ridges)
• shiny green on top
• paler green below

Flowers:

• yellowish-green
• 8–50” stalked
• umbrella-shaped clusters in the axils of leaves
• 5 sepals, petals, and stamens
• 3–4 mm. diameter

Fruit:

• drupe
• bright red then matures to deep purple or black
• “edible but not incredible”

Other characteristics:

• tree 15–30 ft. (5–10 m.) high
• thin, smooth silver-gray bark

Relevant info:

• bark can be chewed or boiled in tea for laxative effect
• used for this purpose historically by PNW Natives and more recently by Europeans in pill form
• in the PNW, the species has long been known as a member of Rhamnus, but many authorities (including the UW Herbarium) now assign it to Frangula
  • Frangula is considered by some authorities to be a subspecies of Rhamnus

Ecology & Adaptations:

• native to British Columbia south to California, east to Montana and Idaho
• in Washington, occurring on both sides of the Cascades crest
• found in moist, shaded sites
• coniferous forests understory, mixed forests, forest edges, deciduous woodlands, stream banks, coastal sage scrub, non-serpentine substrates
• low to moderate elevations (0–2000 m.) in the mountains
• pollination – attracts an abundance of bees and other pollinators during its long flowering season (Apr-Jun in PNW)
• seed dispersal – fruits are an important food for songbirds, pileated woodpeckers, band-tailed pigeons, and other wildlife, which aids dispersal
• vegetative reproduction:
  • sprouts from the root crown following damage from low-intensity fires
  • can spread by layering
• herbivore defense – bark contains anthraquinare derivatives, which cause peristalsis of large intestine, as well as tannins, and resins that taste extremely bitter, may temporarily numb the taste buds, and interfere with digestion (as a laxative)
• wildlife:
  • winter browse for mule deer, elk, Olympic black bear, Oregon gray fox, raccoon, and ring-tailed cat
  • drupes are eaten by drupes are eaten by several species of birds, including the Oregon ruffed grouse and band-tailed pigeon
• very shade tolerant – tall spindly form indicates carbon allocation to stems, which is typical of shade-tolerant plants where elongation and structural support are critical for efficient harvesting of light in the understory