Mammillaria polythele Mart. · Many-tubercle cactus · Amethyst crown

🌱 Morphology
Cactus with a globose to cylindrical body, generally solitary although it may branch with age, bluish-green and up to 40–50 cm tall and 8–10 cm in diameter. The tubercles are large, conical or pyramidal, arranged in a spiral, with white wool in the axils. Young plants usually have only 2 spines, while with age they can develop 3–7 or more, brown to reddish, up to 2.5 cm. Some cultivated forms are practically spineless.

🌍 Distribution, habitat and family
Endemic to Mexico, mainly Guanajuato, Hidalgo and Querétaro, with populations also in other states depending on the taxonomic treatment. It grows at approximately 1,700 and 2,400 m, in xerophytic scrubland, rocky slopes and open oak forests, frequently among dense vegetation and in partial shade, on mineral and generally calcareous soils. It belongs to the Cactaceae family, Cactoideae subfamily, Cacteae tribe. Joël Lodé maintains Mammillaria polythele as an independent species and also recognizes the durispina and obconella subspecies.

❄️ Temperature · USDA Zone 9a
Tolerates minimum temperatures of up to −5 ºC when dry and with well-acclimatized specimens. Although it comes from high altitudes, resistance depends heavily on the state of dormancy and keeping the substrate completely dry during the cold.

☀️ Lighting
Needs lots of light, but it should not be confused with a strictly desert cactus: in nature it also grows protected by vegetation. Gentle direct sun or very intense light is recommended, with gradual acclimatization and light protection during extreme heat episodes. During active growth, approximate DLI PAR of 20–30 mol·m⁻²·day⁻¹.

💧 Growth cycle and watering
Winter dormancy. Keep practically dry during the winter. In spring and summer, deep watering is recommended when the substrate is completely dry, then letting it dry out completely again. The cold and dry period is especially important to induce good flowering.

🌸 Flowering
Can flower from about 3–4 years from seed, when it reaches sufficient size and has properly gone through winter dormancy. It produces small flowers pink, magenta to purple-red, approximately 1 cm, arranged in a crown around the apex.

The documented phenology is especially interesting: in a population studied in Jalisco, buds in June and flowering from June to October were observed, followed by fruiting in January. Therefore, it presents a prolonged flowering within the same season, compatible with successive flowering pulses; however, a fixed number of 2–3 waves has not been documented with sufficient precision, so it should not be stated that it necessarily produces three pulses every year. The flowers are hermaphrodite and diurnal anthesis.

🌿 Nutrition
During the active growth period, a fertilizer with a high content of assimilable calcium and low nitrogen levels is recommended, such as Desert CHOICE® Cactaceae, applied once a month when watering. Before flowering, it can be supplemented with Desert CHOICE® Flowering.

This is an inimitable xerophyte cultivated in Madrid in a technological square pot and with the substrate activated with mycorrhizal fungi and biofungicides.

📏 The size of our xerophytes from the basic collection are as follows:

S -> 9cm x 9cm

M-> 14cm x 14 cm

 * Since it is an online purchase, the appearance of the sent specimen may vary slightly from the product image. The photo description specifies the plant measurements, but this can also vary slightly, because, it is a living being! Each of the plants at Desert CITY has unique characteristics.