Mammillaria matudae
Family: Cactaceae​
​Common Name: thumb cactus
Origin: Mammillaria matudae is endemic to Mexico, located between the states of Michoacán and Guerrero, 700-1250 meters above sea level.
Description: M. matudae is a cylindrical columnar cactus with a tidy form, white radial spines, and a white to black central spine. As the cacti ages, it develops a sprawling appearance, and the central spine becomes dull in color, turning brown or gray. The thumb cactus blooms in March and April, forming a thick ring of 2-3 magenta flowers from the tip of the cactus, followed by red fruits.
  • Interesting Features:
    • Mammillaria matudae possesses latex sap and is resistant to verticillium wilt.
    • While many cacti store water in the ribs, the thumb cactus stores water in raised tubercles, which will expand upon irrigation.
    • M. matudae is named after the Japanese botanist Dr. Eiji Matsuda, Professor of Botany at the University of Mexico, 1950.
  • Uses: Although no specific ethnobotanical use exists for the species M. matudae, the Mammillaria genus has been utilized by Indigenous people for a variety of purposes. These include as a poison, insecticide, snake repellant, and to treat ailments such as dysentery and ear-ache.  

Cultivation and Care:
  • Watering: Low
    • The thumb cactus is drought tolerant and suitable for xeriscaping. As such, water sparsely, only when the soil is dry, and ensure that this species is never exposed to prolonged dampness or left in standing water. Suspend watering in winter to prevent root rot.
  • Soil: The best growth will be observed in well-draining, gritty soil or gravel with a pH from 6.1 – 7.8.
  • Lighting: Prefers full sun to partial shade, and should be planted outdoors for the best growth. However, indoor planting is acceptable if a constant light source is provided.
  • Propagation: M. matudae can be propagated from woody stem cuttings or from seed, sown after the last frost. Allow cuttings to callous over before planting.
  • Cold Tolerance: 25° F, USDA hardiness zones 9b to 11b.
  • Special Accommodations: As this species is fast growing, repotting is necessary once a year, and should be done from spring-summer. Although a desert plant, M. matudae must also receive shade on very hot days to prevent sunburn. Lastly, the thumb cactus is cold tender and very susceptible to root rot, especially under cold conditions. Move indoors during winter. 

Sources:
  1. ​Llifle Encyclopedia of Cacti
  2. World of Succulents
  3. Dr. Duke’s Phytochemical and Ethnobotanical Databases
  4. Plant Lust
  5. Dave’s Garden
  6. Cactus and Succulent Society
  7. Planted Shack