Origin and Habitat: South-west Mexico, Oaxaca, between Nejapa, Juquila, Mixes and Lachiguiri.
Altitude: 2000-2300 metres above sea level.
Nabitat: It grows in barren rocky soils in open pinion forest often embedded in humid moss patches on large exposed rocks. Other plants found in this area comprises: Agave lophanthaSN|25300]]SN|25300]] and Tillandsia pueblensis.

• Mammillaria deherdtiana Farwig
• Bartschella deherdtiana (Farwig) Doweld

• Mammillaria deherdtiana Farwig
• Bartschella deherdtiana (Farwig) Doweld

• Mammillaria deherdtiana var. dodsonii (Bravo) Glass & R.A.Foster
• Bartschella deherdtiana subs. dodsonii (Bravo) Doweld
• Mammillaria dodsonii Bravo

Description: Mammillaria deherdtianaSN|5387]]SN|5387]] is a compact globe-like plant with large, deep-red flowers that originates from the high mountains of Oaxaca. Plants are solitary. Two subspecies are recognized, the nominate and ssp. dodsonii (Bravo) D.R.Hunt. The distinctions between the subspecies are somewhat ambiguous and even if it appears that there is some geographic separation between them, field studies have established a seamless transition between Mammillaria deherdtianaSN|5387]]SN|5387]] and M. deherdtiana ssp. dodsonii. The standard M. deherdtiana has more numerous spines, usually including 1 or more straight, reddish-brown centrals. Both M. deherdtiana and M. deherdtiana ssp. dodsonii are wonderful, large-flowered and with attractive spination, but fairly slow growing. They flower in summer.
Stems: Solitary, depressed globose, to 2-5 cm high and 4.5-5 cm in diameter.
Roots: Thickened fibrous from the basal portion of stem, but lacking the tuberous tap root.
Tubercles: Conical, up to 19 mm long, dark green, in 8 and 13 spirals with watery sap. Axils slightly woolly or naked.
Areoles: Obovate, 4 mm long and 2 mm. wide, covered with pure white felt, , set obliquely at the top of the tubercle. In the case of new areoles the upper half bears minute reddish brown deciduous bristles. Naked or with traces of white wool.
Central spines: 1-6, sometimes absent, fine, needle-like, nearly erect, reddish brown to yellow, 3-7 mm long. The principal one slightly declined, stout, 3 to 5 mm long.
*Radial spines: 20-36, fine, needle-like, yellow, becoming white, 3-6(-20) mm long.g, the upper ones slightly curved, the lower ones directed forward and occasionally curving laterally upward or downward, longer and stouter. Light yellow at first but soon passing to a glistening white with occasional reddish brown tips.
Flowers: Long funnelform, opening widely, bright rose violet, to 50 mm in diameter. Floral tubes long, to 20 mm long, flesh coloured, with small olive green scales, the ovary embedded in the stem between the tubercles. Outer perianth segments up to 10 mm. long, lanceolate, flesh coloured on the margins and greenish in the middle. Inner perianth segments up to 23 mm. long and 4 mm wide, oblanceolate with acuminate tips, bright rose-violet, with a darker mid-stripe and tip. Style, longer than the stamens, white, flushed slightly with violet at the base and beneath the white mid-stripe and tip. Style, longer than the stamens, white, flushed slightly with violet at the base and beneath the white stigma lobes, which are four in number. Filaments erect, the same colour as the style; anthers egg yolk yellow.
Fruits: Globose, 3 to 4mm. in diameter, half embedded in stems, white at the base, the exposed portion pale green, with the dried perianth persisting.
*Seeds: 2 mm long and 1mm wide, dark brown to black and minutely pitted.

Bibliography: Major references and further lectures
1) Mammillaria deherdtiana in: S.J. Farwing, Cactus and Succulent Journal of America, 41, 27(1969)
2) Arias, S., Cházaro, M., Hernández, H.M. & Gómez-Hinostrosa, C. 2013. Mammillaria deherdtiana. The IUCN Red List of Threatened Species 2013: e.T151790A561803. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T151790A561803.en. Downloaded on 09 July 2017.
3) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
4) John Pilbeam (1999) “Mammillaria The Cactus File Handbook” Nuffield Press.
5) John Pilbeam “Cacti for the Connoisseur: A Guide for Growers & Collectors” Timber Press, 01 July 1987
6) Edward F. Anderson “The Cactus Family” Timber Press, 2001
7) Acosta, S., A. Flores, A. Saynes, R. Aguilar & G. Manzanero. 2003. “Vegetación y flora de una zona semiárida de la cuenca alta del río Tehuantepec, Oaxaca, México”. Polibotánica: 125-152.
8) SEMARNAT. 2010. "Norma Oficial Mexicana NOM-059-SEMARNAT-2010, Protección ambiental-Especies nativas de México de flora y fauna silvestres-Categorías de riesgo y especificaciones para su inclusión, exclusión o cambio-Lista de especies en riesgo. Diario Oficial de la Federación".
9) H. Manitz, Jena, “Excerpta Botanica: Taxonomica et chorologica”, Volume 48 Fischer, 1989
10) The Journal of the Mammillaria Society, Mammillaria Society, 1977
11) 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
12) Roger Spencer "Horticultural Flora of South-eastern Australia. Volume 2, Flowering Plants: Dicotyledons. Part 1, the Identification of Garden and Cultivated Plants" UNSW Press, 1995
13) Clive Innes, Charles Glass "Cacti" Portland House, 01/May/1991
14) Walther Haage "Kakteen Von A Bis Z: Ein Ratgeber Fur Den Kakteenfreund Mit Kurzbeschreibung Der Wichtigsten Bis Ende 1979 Benannten Gattungen und Arten Von Kakteensowie Der Dazugehorigen Wissensgebiete" Neumann, 1983

Cultivation and Propagation: Mammillaria deherdtianaSN|5387]]SN|5387]] is relatively rare in cultivation and has the fame to be difficult to grow on its own roots because it is very sensitive to overwatering (rot prone) and slow-growing. This species is adapted to very shallow organic soil (grows in moss patches) and requires skilful cultivation, but plants grafted on an hardy stock are easy to grow and no special skill is required.
Growth rate: Slow growing species that will form irregular clumps with time. Flowering 3–5 years from seed.
Soil: Grow it in an open sandy-gritty cactus compost with more organic matter than usual (e.g. add sphagnum, leaf-mould or fine crushed pine bark)
Pots: It needs a relatively shallow pot to accommodate its fibrous roots and provide a very good drainage. They may stay in the same pot for many years.
Watering: Water in moderation, it prefer a completely dry place during winter. Mature individuals easily rot and die especially after planting so be extremely cautious with watering. Keep dry in winter or when night temperatures remain below 10° C. Water it less than average if in bigger pots.
Special need: Provide very good ventilation. Nearly all problems occur as a result of overwatering and poor ventilation, especially when weather conditions are dull and cool or very humid.
Fertilization: Feed them once during the growing season with a fertilizer specifically formulated for cactus and succulents (high potash fertilizer with a dilute low nitrogen), including all micro nutrients and trace elements diluted to ½ the strength recommended on the label. They thrive in poor soils and need a limited supplies of fertilizer to avoid the plants developing excess vegetation, which is easily attacked by fungal diseases.
Exposure: It will do its best with lots of sun and become stressed with inadequate light which could result in poor growth and unnatural shape.
Hardiness: It likes warmth (recommended minimum winter temperature 5° C) however plants kept perfectly dry can can survive low temperatures, approx. -5°, but for safe cultivation it is best to avoid freezing temperatures.
Use: This is a good pot plant suited for a non heated green house. It can be also cultivated outdoors in raised beds, terraces if sheltered from winter rain. This cactus continues to be, a particular prize among collectors
Pests & diseases: These cacti may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:
- Red spiders: Red spiders may be effectively rubbed up by misting the plants from above.
- Mealy bugs: Mealy bugs occasionally they develop aerial into the new leaves and flowers with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Scales, thrips and aphids: (they are rarely a problem.)
- Rot: Rot is only a minor problem if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Propagation: Seeds are quite difficult to germinate and a low rate of success. The seeds can be sown in pots of fine, well-drained sandy soil, any time during the spring when temperatures are warm. Cover the seeds with a fine layer of grit and water from below with a fungicide to prevent damping off. For the 1-2 weeks cover the pots with a sheet of glass/clear perspex to keep the humidity levels high. Remove the glass and replace it with light shade-cloth and mist once or twice a day for the next two weeks after which most seeds should have germinated. From then on mistings can be reduced to every second and then every third day as the little plants grow. Grafting is often used to speed growth rate and to create a back-up for plants in collection.