A tree to 20 ft high with glabrous branchlets, armed with stout thorns. Leaves ovate to broad-ovate or rhombic, rounded to broadly wedge-shaped at the base, 11⁄4 to 23⁄4 in. long and almost as wide, with four to six pairs of sharply toothed, slender-pointed lobes, downy above and hairy on the veins beneath when young, later almost glabrous on both sides. Flowers in downy or hairy corymbs, with ten or fewer stamens; sepals toothed. Fruit crimson, ellipsoid, to 1⁄2 in. wide, with three to five nutlets.
In its typical state this species is confined to Quebec, but var. grayana (Eggl.) Palmer, in which the flowers have twenty stamens and the fruit is more rounded, is of wider distribution. Both are very distinct in the fan-shaped, elegantly cut leaves. The species was introduced early in the nineteenth century (perhaps earlier to France).
C. macrosperma var. acutiloba (Sarg.) Eggl. C. acutiloba Sarg. – C. macrosperma is perhaps not in cultivation in its typical form, but the variety is an old inhabitant of European gardens, once grown as “C. coccinea indentata”. It has the leaves elegantly cut as in C. flabellata but may be distinguished by its glabrous corymbs and entire sepals.