An evergreen climber reaching 12 ft or more high; stems round, armed with sturdy unequal prickles, and furnished with curious minute tufts of bristles; branches square, often unarmed. Leaves of thin texture, triangular, with the base deeply heart-shaped, the apex pointed, the largest 5 in. long, rather more in width, five-nerved, green on both surfaces, with a few grey spots on the upper one, the margins slightly bristly. Flowers in umbels of eight to twelve, the main-stalk as long or rather longer than the leaf-stalk.
Probably a native of N. America, but of unknown origin, having been first described (The Garden, Vol. 56, p. 505) by Lynch from a plant growing against a wall in the Cambridge Botanic Garden, where it has stood for many years. It is a male plant, and may prove to be a hybrid or belong to a species previously named.