|The green, elliptical, slim joints grow up to 10 inches in length. The reddish to grey spines are about 5 to 9 in each areole, and reach 2 inches in length. In summer the bell-shaped, large red flowers are borne singly on the stem tips and then produce yellow, spiny fruit. This genus has the largest membership of sun loving species. Australia has even banned a few because of their rapid growth.