In nature it grows in the vicinity of Tula: a small town in the state of Tamaulipas in Mexico, and from this fact derives its name. It is a generally solitary cactus with a bluish-green globular stem that can elongate and reach 25 cm in height. From the pronounced tubercles come out the spines: the radial ones are short and gray, while the central ones are longer and can take a reddish color at the apex of the stem. At the beginning of the summer its beautiful flowers bloom with a color that varies from white to pink with a darker central stripe.