Mammillaria (probably heyderii) growing with L. williamsii population at El Huizache, SLP.
Mammillaria growing with an L. diffusa population in Queretaro.
Mammillaria growing with an L. koehresii population in Tamaulipas.
This is probably a form of magnimamma.
Mammillaria growing with an L. diffusa population in southern Queretaro.
The one on the left is maybe a dixanthocentron but details are not sharp enough for certainty as two other Mexican species look sort of similar.
Mammillaria growing with an L. williamsii population in Nuevo Leon.
Might possibly be a sanchez-mejorada but the details are not sharp enough for me to tell.
Mammillaria lasiacantha growing with an L. williamsii var. echinata population in West Texas.
Click on photo for more M. lasiacantha images