Mammillaria geminispina

Accession Count: 5
Common Name: twin spined cactus
Family Name: Cactaceae
Botanical Name: Mammillaria geminispina
Synonyms:
Botanical Synonyms: Cactus geminispina
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics: Mammillaria geminispina is a cylindrical cactus with highly variable growth patterns, occasionally clustering in groups up to 3 feet wide (1). Congregations consist of individual stems, 8-18 cm in height and up to 1.5 cm in diameter (2). These cacti may also grow as a single plant, consisting of one to a few light-green stems (3). Extending from axils are protruding tubercles covered with protective latex, and 10-20 long, white bristles (1, 3). Spines are present, and vary among plants – some possessing short, white spines, and others long and dark (1). During the spring, a ring of magenta flowers will form around the top of each stem, occasionally scattered across the entire cactus (2). Eventually, flowers will form red fruits that contain brown seeds (3).
Compound: Mam gem
Geographic Origin: Mexico
Ecozone Origin:
Biome Origin:
Natural History: Mammillaria geminispina was named and described in 1812 by Adrian Hardy Haworth when he returned to London with a specimen from central Mexico (4). The genus Mammillaria stems from the Latin mamilla, teat, for the tubercles on the cacti (5). Meanwhile, the specific epithet, geminispina, refers to “twin spines”, for the pattern of the plant’s central spines (4). Since the beginning of its cultivation, M. geminispina has been valued as an ornamental plant, and its varieties have been popular with horticulturists and collectors world-wide (6). Such popularity has led to the cacti receiving the Award of Garden Merit by The Royal Horticultural Society of London (7).
Cultivation Notes: M. geminispina should be given full sun to encourage thick spine formation, as too little light will result in overly green plants that are susceptible to rotting (8). At the same time, cacti should be watered moderately, allowing the soil to completely dry in between waterings. If M. geminispina are kept overly moist, or deprived of water for too long, then root loss can occur. Suspend irrigation during the winter, and supplement during the hottest summer months (3). To propagate, either use seed, stem cuttings, or offsets from the mother plant. Planting or repotting should be done while the weather is warm, preferably during summer. Before attempting to plant cuttings, allow the wound to callus and the soil to dry completely (9). For the best growth, use a liquid fertilizer every 2-3 weeks when watering.
Ethnobotany: Cactus fruit from the Mammillaria genus have been used by the indigenous Tohono O’odham people as a source of food. Fruit are called “coyote’s paws” to separate from the larger berries produced by the Hedgehog Cactus (2). Additionally, M. geminispina has been used in Mexico as a cancer treatment for excrescence (10).

Height: 0 - 5 feet
Width: 0 - 5 feet
Growth Rate: Slow Growing
Grow Season:
Flower Season: ForeSummer
Color: Pink
Function: Accent
Spread: Spreading
Allergen: Non-allergenic
Invasive: Benign
Toxicity: Benign
Hardy: Hardy
Water Use: Low water Use

Citations:
1. iNaturalist. Retrieved April 18th, 2020.
2. Desert Museum. Retrieved March 30th, 2020
3. Cactus Art Nursery. Retrieved April 19th, 2020.
4. Henry Shaw Cactus and Succulent Society. Retrieved April 19th, 2020.
5. The Cactus and Succulent Society of America. Retrieved April 19th, 2020.
6. Wiersema, J. & Leon, B. (2016) World Economic Plants. CRC Press.
7. The Royal Horticultural Society. Retrieved April 19th, 2020.
8. Plant Lust. Retrieved April 19th, 2020.
9. World of Succulents. Retrieved April 19th, 2020.
10. Johnson, T. (2019). CRC Ethnobotany Desk Reference. CRC Press.
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Mammillaria geminispina