Mammillaria REKOI

Mammillaria REKOI - Rekoi pincushion cactus, Mammillaria rekoi.

Mammillaria is a large genus of low-growing succulent plants in the cactus family (Cactaceae), comprising about 170-200 species distributed mainly across Mexico, as well as in the southern United States, Central America, the Caribbean region, and northern South America. In nature, members of the genus occur in deserts, semi-deserts, dry scrublands, tropical deciduous forests, on limestone slopes, rocky plains, and in mountainous regions with bright sun and well-drained soils.

The plants usually develop as solitary or clumping globose, flattened-globose, cylindrical, or short-columnar cacti. Instead of ribs, they bear individual tubercles, on the tops of which are areoles with radial and central spines. In many species, wool, bristles, buds, flowers, and fruits form in the axils between tubercles.

The flowers usually form in a ring near the apex of the stem and can be white, cream, yellow, pink, red, or purple. After pollination, elongated or club-shaped fruits develop, often red or pink, containing small brown or black seeds with a pitted or reticulate surface.

Mammillaria rekoi has a globose or short-cylindrical stem, solitary or clumping, green, up to 15 cm (6 in) in height, and up to 6 cm (2.4 in) in diameter. The tubercles are conical to cylindrical. The axils sometimes contain milky sap. Radial spines, 20 to 30 in number, are slender, dense, needle-like, white to golden-yellow, reaching up to 6 mm (0.24 in) in length. Central spines, 4-7 in number, are curved or sometimes straight, brown, 1 to 1.5 cm (0.4-0.6 in) in length. The flowers are dark violet-pink, up to 1.5 cm (0.6 in) long.

Mammillaria seeds are small, dark brown or black, rounded or slightly oval. Seed germination under careful greenhouse conditions is usually about 50-80%.

Sowing is carried out in spring or year-round with stable supplemental lighting. A sterile fine-grained mineral substrate based on sifted cactus mix, fine sand, perlite, and mineral grit is used. Seeds are distributed over the surface, gently pressed into the moist soil, and lightly dusted with a minimal layer of fine sand or left uncovered. The sowing is moistened from a spray bottle with a weak solution of potassium permanganate or biofungicide with the addition of a growth stimulant: SUPERthrive, HB-101, Aminozol, Epin, or Zircon. The container is covered with a transparent lid or placed into a greenhouse.

Germination is conducted in bright diffused light at a temperature of about 22-26 °C (72-79 °F), without direct overheating under the sun. The surface is kept moderately moist but not wet; watering is performed only by fine spraying. The sowings are ventilated daily and condensate is removed, as moisture stagnation is dangerous for Mammillaria seedlings and quickly causes fungal issues.

First sprouts may appear in 7-10 days; the typical germination period is 10-21 days, and the maximum possible period under temperature fluctuations or partial drying of the surface can stretch to 4-6 weeks. After sprouts emerge, the cover is opened gradually, and seedlings are kept in bright diffused light with cautious moistening. Pricking out is performed after notable strengthening of the plants and the emergence of the first spines, usually no earlier than several months, with minimal root damage.

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For cultivation, the brightest possible location with several hours of direct sun per day is chosen. South-, southeast-, and southwest-facing windows are best suited, and supplemental lighting is recommended during overcast seasons. After a dark overwintering or repotting, the plant is gradually accustomed to direct sun to prevent burns on the stem.

During active growth, a temperature of about 20-28 °C (68-82 °F) is maintained with good air circulation. The plant is heat-loving and dislikes cold dampness. Overwintering is conducted in bright, dry, and moderately cool conditions, around 8-12 °C (46-54 °F), with almost complete cessation of watering. At lower temperatures, moist substrate is especially dangerous and can induce root rot.

Watering is carried out moderately, only after the substrate has completely dried out. In spring and summer, the soil is moistened in small portions, with mandatory draining of water from the drip tray. In autumn, watering is gradually curtailed; in winter, the plant is kept nearly dry. Water getting into the axils between tubercles is undesirable, especially under cool conditions and weak ventilation.

A loose mineral substrate for cacti with the addition of coarse sand, fine stone grit, pumice, zeolite, perlite, or other inert aerators is used. The organic fraction is added sparingly. Generous drainage is laid at the bottom of the pot, and the container chosen is shallow, stable, and not overly spacious.

Fertilizing is applied only during active growth, once every 4-6 weeks with a weak solution of fertilizer for cacti and succulents with reduced nitrogen content. Excess nutrients cause soft growth and lower resistance to rot. Repotting is carried out in spring as the pot fills with roots; after repotting, the plant is kept without watering for several days. Pruning is not required, and separation of lateral offsets is possible only in well-established specimens.