capitatus – forming a dense head (Latin), referring to dense flower/fruit cluster

Native range: Western North America

Leaves:

• alternate
• 3-5 palmately lobed
• serrate margins (doubly toothed)
• deeply veined
• shiny dark green above
• lighter green and pubescent (star-shaped hairs) below

Flowers:

• terminal domed cluster of small white or pink flowers with pink stamens
• individual flowers:
  • 5 petals
  • 5 sepals

Fruit:

• reddish bunches of small fruits
• individually surrounded by dark reddish brown, papery bell-shaped bracts (1 cm long in total)
• persist through winter

Other characteristics:

• deciduous
• shredding mature bark
• arching branches can reach 12’ tall

Relevant info:

• common restoration plant
• common name refers to the many layers of bark on stems
• Physocarpus opulifolius ‘Diabolo’ – common landscape plant with dark purple foliage, cultivar of species native to east coast of U.S.

Ecology & Adaptations:

• both sides of the Cascades in WA, but chiefly on the west side
• Alaska south to CA, east to Alberta & ID
• moist woods and swamps in the lower mountains (20–1300 m)
• wet, somewhat open places (stream-side thickets, edges of moist woods, coastal marshes, meadows, margins of lakes and streams)
• occasionally on drier, shrubby sites, at low to middle elevations
• well adapted to shade – shade leaves are relatively thin, which maximizes light capture area while minimizing investment in photosynthesizing structure
• vegetative reproduction – extensive root system may sprout new stems
• pollinated by native bees and possibly butterflies
• herbivory and microbial defense:
  • toxic compounds in leaves deter herbivores and prevent microbial infection
  • star-shaped hairs on lower leaf surface discourage herbivores.
• wildlife:
  • provides cover and nesting sites for birds and small mammals
  • low palatability as browse for deer, elk and bear
  • seeds provide food for songbirds