synonym – Rubus nutkanus according to UW Herbarium at the Burke Museum (but not found in other sources)
- nutkanus typically refers to the PNW region, derived from the Europeans’ name for the indigenous people of the NW coast of Vancouver Island
parviflorus – small-flowered (somewhat misleading sine the flowers of this shrub are among the largest flowers found in Rubus)
Native range: Western US and Canada, Northern Midwest US
Leaves:
- alternate
- deciduous
- large
- very soft
- fuzzy pubescence on both sides of leaf
- long, red glandular stalks on leaves and stems
- 3–7 palmately lobed
- deeply cordate base
- maple-leaf shape
Flowers:
- large white
- terminal clusters
- petals like tissue paper
Fruit:
- aggregate of hairy drupelets in flattened hemispherical shape
- red
- edible
- once the fruit is removed, the remaining core resembles a thimble
Other characteristics:
- spreads by rhizome
- stems are erect, tall, and thornless
- sparsely hairy
- red glands (borne on the ends of stalks)
- older stems have shredding bark
- “campers’ toilet paper” (large, soft leaves)
Ecology & Adaptations:
- native to coastal SE Alaska to southern California, east to the Dakotas and New Mexico
- found in open (esp. red alder) to wooded, moist to dry areas, thickets, clearings, stream banks, canyons, grassy meadows, rocky cliffs, avalanche tracks, sand dunes, upper beaches, dry sandy areas
- from sea level to subalpine mountain slopes (0–3,000 m.) in southern portions of its range
- low elevations only in the northern portion
- most abundant in moist to wet conditions
- particularly common in the understory of humid PNW forests
- in Canada, species is an indicator of nitrogen-rich soils
- pollination:
- self-pollinates but has larger fruit production when cross- pollinated
- large quantities of nectar in flowers attract pollinators, especially bees that feed on nectar and collect pollen.
- reproduces vegetatively - forms clumps or dense thickets through an extensive network of rhizomes
- fire tolerance:
- after fire, sprouts from rhizomes
- most fires only top-kill thimbleberry shrubs, except where high temperatures penetrate deep into the mineral soil layer
- seeds dispersed by birds (robins, crows, Swainson’s thrushes, band-tailed pigeons) and mammals (squirrels, chipmunks, woodrats, voles, mice, and American martens) that eat the fruit
- herbivore defense – tannin and cardiac glycoside contents render this plant unpalatable to moose, a generalist, and other animals
- succession – although generally present throughout all stages of forest succession, thimbleberry is most characteristic or common in early-seral forest communities