Acharagma galeanense is a single-locality limestone-calcicole cactus from Galeana, Nuevo Leon, Mexico; elevated to species rank by Lode 2017; cylindrical prostrate stems and cream-yellow flowers distinguish it from its sister taxon A. roseanum. Cactaceae.
Stenocactus multicostatus is the brain cactus of northeastern Mexico, holding the record for rib count in any cactus with up to 150 thin wavy ribs on a globose body under 15 cm wide. CITES Appendix II, IUCN Data Deficient.
Stenocactus coptonogonus is the genus outlier: only 10 to 15 straight ribs and flat blade-like spines on a body that resembles Ferocactus at a glance. The type species of Echinofossulocactus. IUCN Least Concern, CITES Appendix II.
Complete guide to Mammilloydia, the snowball cactus genus. One accepted species, M. candida, from Coahuila and Nuevo Leon limestone scree. CITES Appendix II.
Acharagma roseanum is a miniature limestone-calcicole cactus from southeastern Coahuila and Nuevo Leon, Mexico; Vulnerable on the IUCN Red List, clustering habit with cream-to-pink flowers and a distinctive pale gold spine blanket. Cactaceae.
Mammilloydia candida is the snowball cactus of northeast Mexico, its body entirely hidden beneath 50-120 pure-white pectinate spines. Segregated from Mammillaria by Buxbaum in 1951 on smooth-seed and perisperm-absent characters; POWO continues to accept the monotypic genus. Cactaceae, IUCN Least Concern.
Leuchtenbergia principis is the agave cactus of the central-north Mexican Plateau; long pencil-like tubercles 6-12 cm tipped with flexible papery spines, large yellow apical flowers, the most agave-like silhouette in Cactaceae. IUCN Least Concern. Monotypic genus.
Strombocactus corregidorae is the Queretaro canyon cactus described by Arias and Sanchez in 2010; darker, heavier-spined and more globose than its sibling S. disciformis. CITES Appendix I. NOM-059 Amenazada. Cactaceae.
