"Twinberry is a non-twining shrub with its opposite leaves darker green above and paler and more hairy below. The flower stems usually turn reddish to purplish, each leading to two delicately perfect twin flowers, the pair held attractively in a cup-like set of bracts, and each corolla like a perfect little narrow bell. The twinberries or fruits are black and not edible."
—Dorothy King Young,
Redwood Empire Wildflowers, 1964