P. fruticosus var. cardwellii (Howell) Krautter
P. fruticosus subsp. cardwellii (Howell) Piper
, differing in the always toothed leaves obtuse or rounded at the apex, and the darker, sometimes red-purple flowers. It occurs in Oregon on the western side of the Cascade mountains and in the coastal range, and extends into S.W. Oregon. It was introduced to Kew in the 1930s by means of seeds received from Lester Rowntree of California.