About Rapicactus beguinii (N.P.Taylor) Lüthy
Rapicactus beguinii (N.P.Taylor) Lüthy is a solitary cactus with fibrous roots. Its stems are grayish to bluish-green, spherical to short cylindrical-spherical, growing 7 to 15 cm (2.8 to 5.9 in) tall and 3 to 10 cm (1.2 to 3.9 in) in diameter. The stems bear conical tubercles that reach 2 to 3 mm (0.079 to 0.118 in) in height. This cactus produces 2 to 3 slender, straight, spreading central spines, each 12 to 15 mm (0.59 in) long; these spines are white to yellowish-brown, with darkening at the tips. It also has 9 to 27 straight, spreading radial spines that measure 4 to 6 mm (0.24 in) long, which are white and also darken at their tips. Its flowers are 1.2 to 1.8 cm (0.47 to 0.71 in) in diameter, and range in color from whitish or yellowish to magenta. The plant's greenish-magenta fruits are 16 to 18 mm (0.63 to 0.71 in) long. This species grows in pine forests and on steep cliffs across the Mexican states of Nuevo León, Coahuila, Zacatecas, San Luis Potosí, and Tamaulipas, at elevations between 1900 and 2100 meters.
