Rapicactus booleanus is a species of plant in the family Cactaceae.
Rapicactus booleanus grows solitarily with a tuberous root connected to the stem by a narrow neck long. The grey-green stems are spherical, obovate to turbinate, narrowing at the collar, and measure tall and in diameter. The hard, spirally arranged tubercles are closely set, 4-angled, rhomboid, somewhat flattened and almost truncated above, and somewhat horny or keeled below. There are 2 erect central spines, whitish with dark brown tips, measuring long. Around 18-20 radial spines are white and measure long. Flowers are pale to dark magenta with darker midstripes, blooming on summer days, and are long and in diameter. The fruits are dark green to purple, measure long and in diameter, and split open when ripe.[1]
Plants are found growing in gypsum outcrops near San Roberto, Nuevo León and in general Mexico.[2]