Arborescent shrub or tree to 12 m; thorns 1-2 cm, lateral on the twigs and also terminating short stout branches; lvs ovate to rhombic or obovate, cuneate to truncate at base, glabrous, or sometimes slightly hairy beneath when young, dark green, deeply cleft with 3-5(7) lobes, the veins running to the sinuses as well as to the points of the lobes; petioles from 1/4 to fully as long as the blade; fls 0.9-1.2 cm wide, in glabrous or slightly villous compound cymes; sep deltoid, entire; fr red, 5-8 mm thick, with thin flesh and usually a single nutlet. Native of Europe and w. Asia, often escaped from cult. in our range. (C. oxyacantha, a rejected name)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.