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A hybrid of which C. purpureus is one parent. The identity of the other parent is uncertain; it is now usually considered to be C. hirsutus, but C. elongatus has been suggested. It has inherited the characters and general aspect of C. purpureus, having glabrous stems and similar foliage, but is a sturdier, taller, and more rounded bush, 2 ft or more high. It differs from C. purpureus in having the flowers a distinct compromise between yellow and purple, and in having a quite hairy calyx. It has been known for about eighty years, and is a very desirable broom.