Mammillaria heyderi var heyderi
In habitat, folks often walk over and past this plant because it is camouflaged so well that the uninterested and unaware often do not see it. The solitary bodied plant can get to about 4" in diameter and is nearly flat. It is covered with a multitude of short, stout, brown spines which give it a pin cushion-like effect. When growing in brown gravely soils, or amongst short grasses, it is virtually invisible. If you are in a habitat where this plant is present, and your eyes get keyed to it, you can suddenly see them everywhere; but, if you are a plodding fool you are unlikely to notice this fantastic cactus. This species has off-white colored flowers that occur mainly in the spring. A very hardy cactus if given a dry, well drained soils in full-sun.

