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Although undoubtedly related to the crus-galli group of thorns, this does not appear to have been found wild in N. America, although it has been suggested that a wild putative hybrid between crus-galli and macracantha is the same. This theory is supported by the shape of the nuts, which have hollows on the inner faces as in macracantha, only not so deep. Whatever its origin, C. prunifolia is one of the most admirable of all thorns. It is a tree up to 20 ft high, forming a rounded head of branches, wider than high, often reaching to the ground, and densely leafy; young shoots glabrous; spines rigid, sharp, 11⁄2 to 3 in. long. Leaves varying from roundish ovate or oval to obovate; 11⁄2 to 31⁄2 in. long, 11⁄2 to 21⁄2 in. wide; toothed nearly to the base, glabrous and brilliant dark green above; pale, dull and either glabrous or slightly downy on the midrib and veins beneath. The leaves turn a rich glowing crimson in autumn. Flowers 3⁄4 in. diameter, produced during June in rounded corymbs with hairy stalks; calyx-lobes glandular-toothed, not downy; stamens ten to fifteen, anthers pink. Fruit rich red, 5⁄8 in. long, globose, falling with the leaves in October. From crus-galli it is well distinguished by its wider leaves, hairy flower-stalks, and early falling fruit.
C. ovalifolia (Hornemann) DC., differs in the following respects from prunifolia: leaves somewhat downy on both surfaces; stamens fifteen to eighteen; but there are intermediate forms.
It was stated that the autumn colour of this species is ‘a rich glowing crimson’. This is true of some trees, but unfortunately not of all.