Origin and Habitat: Garden origin (Nursery selected white flowering selection). The natural species is endemic to a very small area, Between Ciudad Victoria and Iaumave, Tamaulipas, Mexico, Northern America.

• Mammillaria carmenae f. albiflora hort.

• Mammillaria carmenae Castañeda
• Escobariopsis carmenae (Castañeda) Doweld
• Mammillaria carmenae f. albiflora hort.
• Mammillaria carmenae f. cristata hort.
• Mammillaria carmenae f. rubrispina hort.

Description: Mammillaria carmenaeSN|20921]]SN|20921]] is a solitary or clustering globular cactus.
Stems: Globose to ovoid, 4 - 10 cm high, 3 - 5 cm in diameter. Without latex.
Tubercles: Conical.
Axil: Woolly and bristly.
Radial spines: More than 100, soft, fine, flexible, star-like, pure white 5 mm long.
Central spines: There are no central spines.
Flowers: Daytime pure white, to 11 mm long.
Blooming season: Plants blooms at the same time in late winter-early spring and are very generous with their flowers.
Remarks: The point of interest of "forma albiflora" are the white spines and flowers..

Bibliography: Major references and further lectures
1) Nathaniel Lord Britton, Joseph Nelson Rose “Cactaceae: Descriptions and Illustrations of Plants of the Cactus Family” Courier Dover Publications, 1963
2) James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug./2011
3) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
4) Edward F. Anderson “The Cactus Family” Timber Press, 2001
5) Clive Innes, Charles Glass “Cacti” Portland House, 01/May/1991
6) Fitz Maurice, B, Fitz Maurice, W.A., Hernández, H.M., Sotomayor, M. & Smith, M. 2013. "Mammillaria carmenae." The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 21 December 2014.

Cultivation and Propagation: It is a relatively rapid growing species. This is easily grown into clumps, but it does often have an irregular pattern of offsetting. Water regularly in summer, but do not overwater (Rot prone) Use pot with good drainage and a very porous potting media, keep dry in winter. Feed with a high potassium fertilizer in summer. It is quite frost resistant if kept dry, hardy as low as -5° C. Outside full sun or afternoon shade, inside needs bright light, and some direct sun.
Easily clustering and easily flowered. Most plants will offset readily, and clumps can be produced in a few years.
Propagation: Division, direct sow after last frost.