Arrojadoa rhodantha

Arrojadoa rhodantha is a species of cactus with a shrubby growth form. Its stems can grow vertically or at an angle, and can reach 2 m in height. The roots are fibrous. The stems are dark green in color, cylindrical, segmented, and measuring 2-5 cm in diameter. The stems have 10-12 very shallow ribs, and the areoles are 10-12 mm in length with spines that are white to yellow-brown in color. There are 5-6 central spines, which are strong and grow to 3 cm in length. The radial spines are approximately 20 in number per areole, and can grow to 1.2 cm in length. The cephalia at the ends of the segments are made from brown woolly trichomes and red-brown bristles. The flowers are red-purple and magenta, and can grow to 3.5 cm in length and 1.2 cm in diameter. The fruits are spherical in shape and red in color, and can reach a diameter of 2 cm.

Arrojadoa rhodantha is native to Brazil (from southeastern Piauí to north-central Minas Gerais) and is found primarily in the seasonally-dry tropical biome. It grows in rocky areas.