cornuta – horned or horn-shaped, from Latin cornum for horn, referring to “beak”

Native range: North America

Leaves:

• alternate
• simple
• elliptic to oval
• base of blade flat or somewhat heart-shaped
• leaf margins doubly serrate
• 1.5–4.5” long
• 1–3” wide
• very soft densely pubescent leaves
• turn yellow in fall

Flowers:

• monoecious
• catkins:
  • males
  • 1” long
  • emerge before the appearance of leaves
• female flowers:
  • enclosed in bracts at the tip of the twigs
  • only the red stigmas visible
  • emerge after males

Fruit:

• spherical
• edible, beaked nut (hazelnut)
• surrounded by husk (involucre, or cluster of bracts):
  • originating at the nut base
  • light-green, covered with stiff prickly hairs
  • projecting 1–1.5” beyond the nut into a “beak”
• clusters of 2 or 3 at ends of branches

Other characteristics:

• deciduous
• many stems radiating from single root crown
• 4–8’ wide, up to 15’
• ~ bristly-hairy (long white hairs) on young twigs
• slender new growth creates a “zigzag” pattern at end of branch

Relevant info:

• important food for NW tribes (picked in early autumn, stored until ripe, eaten fresh or roasted)
  • used them for trading, for instance with the Lewis and Clark Expedition and with plant explorer David Douglas
• in some areas, productivity of shrub is enhanced by burning
• in Oregon’s Willamette Valley, there are 30,000 acres of commercially grown European Hazelnut or Filbert (C. avellana) and the nuts are often distributed by birds to natural area
  • the resulting shrubs are sometimes confused with the native hazelnut
• used in hazelnut breeding programs to produce high-yield, disease-resistant hybrid cultivars (for instance, resistance to eastern filbert flight fungus)
• the variety native to the Pacific Northwest and West Coast is C. cornuta var. californica
  • indicator species for low-elevation, warm sites with well-drained soils in western Oregon and southwestern Washington
• eastern variety (var. cornuta) is rhizomatous and often considered “weedy”

Ecology & Adaptations:

• widespread in North America from British Columbia to Newfoundland, south to California, Colorado, Missouri, Ohio, and Georgia
• in WA, on both sides of the Cascades, and in the SW and NE portions (cooler elevations) of the eastern side of the state
• found in moist but well-drained sites, forest edge and shady openings, thickets, clearings, in coves and canyons, rocky slopes and well-drained streamside habitats
• at low to middle elevations (100–500 m)
• wind pollinated
• seed dispersal:
  • occurs via birds and rodents that cache seeds, such as Steller’s jays and scrub jays and red squirrels and least chipmunks
  • greater than 66% of scatter-hoarded nuts were consumed or relocated by the rodents
  • however, remaining cached nuts were protected by litter and/or soil and had a better chance of germinating and establishing than uncached nuts
  • Douglas’s squirrels, and golden-mantled ground squirrels also consume seeds
  • especially important to squirrels and other acorn-eating animals in times of oak (Quercus spp.) acorn crop failure
• vegetative reproduction:
  • spreads widely by suckers (new stems from roots)
  • may also layer
  • C. c. var. california typically does not have rhizomes (unlike eastern variety)
• fire tolerance:
  • via seed establishment on new (open) sites
  • also re-sprouts from root crown after top-kill by fire
• wildlife – harvested shortly after ripening by squirrels and other cache-forming animals
• herbivore/microbial defense:
  • hairy leaf texture reduces palatability
  • caffeic acid, gallic acid, and vanillic acid provide anti-fungal and anti-bacterial protection for the seed (nut)
• moderately shade-tolerant, but abundance decreases with canopy closure and time since disturbance