Kadenicarpus horripilus is a species of plant in the family Cactaceae.[1]
It is an endangered species, threatened by habitat loss.
Kadenicarpus horripilus often grows sprouting with olive-green, spherical to elongated spherical bodies and fibrous roots. The bodies reach growth heights of and a diameter of . Their clearly pronounced conical cusps are high. The plant usually a single, protruding, straight, whitish central spine that is dark at the tip. It reaches a length of . The 12 to 14 straight radial spines are white with a dark tip, protruding and long.
The flowers are magenta with a white throat. They are long and have a diameter of . The elongated, greenish-red fruits turn yellowish-brownish when ripe. They are long and reach a diameter of .[2]
It is endemic to Hidalgo state in Mexico. Its natural habitat is hot deserts.
It was first described as Mammillaria horripila in 1838 by Charles Lemaire.[3] The specific epithet horripilus is derived from the Latin words horrere for 'shudder' and pilus for 'hair' and refers to the thorns of the species. Monserrat Vázquez-Sánchez placed the species in the genus Kadenicarpus in 2019.[4] Further nomenclature synonym are Echinocactus horripilus (Lem.) Lem. (1839), Neolloydia horripila (Lem.) Britton & Rose (1923), Gymnocactus horripilus (Lem. ex C.F.Först.) Backeb. (1951), Thelocactus horripilus (Lem.) Kladiwa (1970), Thelocactus horripilus (Lem.) Kladiwa & Fittkau (1975), Turbinicarpus horripilus (Lem.) V.John & Říha (1983), Bravocactus horripilus (Lem.) (1998) and Pediocactus horripilus (Lem.) Halda (1998)