Mammillaria karwinskiana ML352
10km from Teotlan del Valle, on road to Antonio Cuajimoloyas, Oaxaca
 

Description: Solitary, or slowly branching dichotomously (or basally) with cream coloured 'snowy' tomentum on the top of the plant.
Stem: Globose to short cylindrical blue-green to dark green up to 12 cm in diameter, 8 20 cm tall. With latex.
Axil: Very woolly with tufts of white hair and  long white bristle.
Tubercles: Firm, pyramidal, arranged spirally with 13-21 parastichys
Radial spine: Usually 6, awl-like, straight to slightly curved, cream to reddish tipped with brown, becoming chalky white with age, 4 - 30 mm long, upper and lower ones longest.
Central spine: Absent
Flower: Funnelform, cream-white to yellow with purplish midveins, to 25 mm long and 15 mm in diameter. Blooms adorn the crown of the plant usually in a ring in the growth of the previous year.
Flowering time:  Early spring.
Fruit: Red elongated and quite attractive.
 

M. karwinskiana  is a very variable species and some of the different growing forms has been for a long time considered separate and distinguished variety, for example:

• ssp. karwinskiana has medium yellow flowers with purpleish midviens; No central spines and 6 radial spines.
• ssp. collinsii has white flowers with deeper pinkish midveins; One central spine and 7 radial spines.
• ssp. beiselii has white flowers with red tinted midveins; One central spine and 5-8 radial spines.
• ssp. nejapensis also has white flowers with red tinted midveins, but the spines are larger and white and has much more wool; No central spines and 3-5 radial spines per areole.

Cultivation: They are easy to culture and make interesting specimens for any collection and over time will produce large clumps. It grows by dichotomously dividing and also by producing offsets and don't requires any special treatment, but need as much light as possible without burning the plant to keep the stems compact.  Need a well-drained soil mix. Water well and then allows to dry thoroughly before watering again during the growing season. Doesn't like much, if any, winter water, can survive short exposures to freezing temperatures (-4° C.) if properly hardened off and kept dry.

Propagation: Mammillaria karwinskiana is best propagated from seed. Seed readily germinates at 20°-22°C, or by offsets if available.

Scientific name: Mammillaria karwinskiana
First description by Martius, Nov. Act. Nat. Cur. 16(1): 335 (1832)

Origin:  Mexico Oaxaca, (Morelos, Michoacan, Puebla). Altitude 1.200 - 2.100 m.

Conservation status: Listed in CITES appendix 2.

Synonyms:

• Neomammillaria karwinskiana (Mart.) Britton & Rose
• Mammillaria pyrrhocephala,
• Mammillaria multiseta,
• Mammillaria strobilina,
• Neomammillaria praelii,
• Cactus praelii,
• Mammillaria viridis var. praelii,
• Mammillaria praelii,
• Neomammillaria neomystax,
• Mammillaria neomystax,
• Mammillaria nagliana,
• Mammillaria fischeri,
• Mammillaria ebenacantha,
• Mammillaria conzattii,
• Mammillaria pyrrhocephala var. confusa,
• Neomammillaria confusa,
• Mammillaria confusa,
• Cactus karwinskianus,
• Mammillaria tropica,
• Neomammillaria karwinskiana,
• Mammillaria jozef-bergeri