Acanthocalycium ferrarii – Rausch 1976
- – Acanthocalycium variiflorum Backeberg 1966, not validly published
Plants solitary, globose to cylindrical, green, to 12 cm (4.7 in) in diameter. Ribs as many as 18, rounded, swollen at areoles. Areoles oval, whitish. Spines horn colored to brown, usually straight, awl shaped. Central spines 1-4, to 1.5 cm (0.6 in) long. Radial spines 7-9, to 2 cm (0.8 in) long.
Flowers yellow to orange-red to carmine, to 5.5 cm (2.2 in) long and 5 cm (2 in) in diameter. Fruits oval, to 10 mm (0.4 in) long and 8 mm (0.3 in) in diameter.
Distribution: Tucuman, Argentina.
References: Anderson E.F. - The Cactus Family