Pacific Blackberry - Rubus ursinus
Very common in the Park up to 3500 feet, on disturbed ground as well as in openings in dryish forests. It grows both as an upright shrub and as a trailing groundcover. Photographed (left and center) at Sunshine Point on May 18, 2014, and (right) at the Ohanapecosh campground on July 24, 2011.