by Emile Abbott.(1) A BetterPhoto Members Favorite!
Mammillaria heyderi. The generic name in latin means breast or nipple and refers to the nipple like tubercles. The dark green stem of te pincushion cactus is a low hemisphere with a flatten or depressed top. The spines grow at the tips of the prominent tubercles. When grown in limestone regions such as this the spines are white. It is common in this area of West Texas and in Big Bend.