Mammillaria dawsonii (Houghton) R.T.Craig, Mammill. Handb.: 67. 1945 Mammillaria dawsonii (Houghton) R.T.Craig, Mammill. Handb.: 67. 1945is new combination for Neomammillaria dawsonii Houghton in Cact. Succ. J. (Los Angeles) 7: 88. 1935Taxon for this nameMammillaria dawsonii (Houghton) R.T.Craig