Mammillaria retusa:

Mammillaria retusa:

Mammillaria retusa Pfeiff., Cactaceae: See Coryphantha retusa (Pfeiff.) Britt. & Rose.




Mammillaria retusa Scheidw. ex Labour., Cactaceae: See Coryphantha elephantidens (Lem.) Lem.

I have no articles for this botanical term, but there might be some for the next level down (if found).