Curator reference for Astrophytum asterias f. nudum: the fleck-free horticultural form of the Tamaulipan star cactus, with taxonomic standing, diagnostic characters, kabuto relationship, and cultivation differences from typical asterias.
Curator reference for Astrophytum asterias: the Tamaulipan star cactus, CITES Appendix I and US ESA Endangered, with taxonomy, habitat, morphology, cultivation, and collector identification from Starr County Texas and northeastern Mexico.
The white-flowered form of Mammillaria herrerae from calcareous slopes south of Pozos, Guanajuato. Critically Endangered, with roughly 5,000 individuals in a single threat-based location.
Cross-spined gypsum-cliff endemic from the Puebla-Oaxaca border, almost always forking dichotomously at maturity into the paired owl-eye heads collectors prize.
Mammillaria huitzilopochtli is an Oaxacan cliff-obligate endemic from the Tehuacán-Cuicatlán valley, wrapped in pectinate white radials and named for the Aztec sun-and-war god.
Northern Coahuila miniature with umbrella-branched spine tips unique in Cactaceae, cryptocarpic fruit retained inside the stem, and magenta flowers larger than the plant body.
Oaxaca shale-hill geophyte described by Linzen in 2014; the only Mammillaria saboae-group species south of the Trans-Mexican Volcanic Belt, with a tuberous taproot heavier than the visible body and cryptocarpic fruit.
Shurly 1949 single-cliff endemic on volcanic rock in northern Guanajuato; fewer than 1,000 individuals; 3 cm heads wrapped in glassy white hairlike radial spines.
Rogozinski & P.J.Braun 1985 Guanajuato endemic with plumose feathery white radial spines; IUCN Critically Endangered, approximately 500 individuals across two subpopulations.
Mammillaria pectinifera is a Tehuacán-Cuicatlán Valley endemic: a flat-globose 2–3 cm miniature with 20–40 pectinate white radial spines, pink-to-white flowers with darker midstripes in April–May, and CITES Appendix I protection. Endangered (IUCN 2013) across roughly 18 fragmented subpopulations.