Curator reference for Mammillaria humboldtii, the snow-white snowball cactus of the limestone cliffs of Hidalgo and Querétaro, Mexico. Taxonomy, habitat, morphology, identification against M. herrerae, IUCN Critically Endangered status, and cultivation notes for serious collectors.
Cochemiea setispina care and identification. One of the two original pre-revision Cochemiea species; compact granite-slope endemic of central Baja California with dense white bristly spines and spring-blooming zygomorphic scarlet flowers; confirmed calcifuge; CITES Appendix II, not formally assessed by IUCN.
Cochemiea guelzowiana care and identification. Formerly Mammillaria guelzowiana; Durango limestone endemic with massive magenta flowers up to 7 cm diameter on a body under 10 cm across; IUCN Critically Endangered, NOM-059 amenazada, CITES Appendix II.
Cochemiea saboae care and identification. Formerly Mammillaria saboae; a tiny clumping volcanic-substrate miniature from Chihuahua and Sonora bearing pink funnelform flowers 4-6.5 cm across on bodies under 4 cm tall. CITES Appendix II; three subspecies including the coveted goldii and haudeana.
Cochemiea theresae care and identification. A critically endangered Durango miniature with a prominent tuberous taproot, plumose white spines, and disproportionately large magenta flowers; IUCN Critically Endangered, CITES Appendix II.
Cochemiea blossfeldiana care and identification. Compact Baja California endemic with a dark hooked central spine and vivid pink-and-white bicolour flowers; IUCN Near Threatened (2012), CITES Appendix II.
Cochemiea albicans care and identification. Dense pure-white spined Baja California island and peninsula species; cylindrical clustering body with actinomorphic white-pink flowers; IUCN Least Concern, CITES Appendix II. Formerly Mammillaria albicans and Bartschella albicans.
Thelocactus rinconensis is the bird’s nest cactus, a flat-domed Chihuahuan Desert calcicole endemic to Coahuila and Nuevo Leon with six named subspecies, pale white-to-pink flowers, and an RHS Award of Garden Merit. CITES Appendix II; subsp. nidulans NOM-059 Threatened. Cactaceae, Mexico.
Thelocactus macdowellii is the Chihuahuan snowball cactus, a densely white-spined calcicole restricted to a narrow limestone corridor east of Saltillo spanning Coahuila and Nuevo León; Near Threatened, CITES Appendix II, NOM-059 Category A. Cactaceae.
Thelocactus setispinus is the easiest gateway species in the genus; hooked central spine, fragrant yellow flowers with a red throat, self-fertile, and a wide range across south Texas, Coahuila, Nuevo Leon, and Tamaulipas. Formerly Hamatocactus setispinus. Cactaceae. IUCN Least Concern.
