Mammillaria RHODANTHA

Mammillaria RHODANTHA - Pink-flowered mammillaria, Mammillaria rhodantha, Mammillaria PFEIFFERI.

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

Plants usually develop as solitary or clustering globose, flattened-globose, cylindrical, or short-columnar cacti. Instead of ribs, they have distinct tubercles, at the apex of which are areoles with radial and central spines. In many species, wool, bristles, buds, flowers, and fruits form in the axils between the tubercles.

Flowers usually form 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 rhodantha is a species with an elongated cylindrical stem that may branch at the base with age. The surface is light green, tubercles are large, and areoles are densely pubescent. Spines are white and golden-yellow, slender, numerous, forming a dense network around the stem.

It blooms from spring to mid-summer. The flowers are bright pink or raspberry, about 2 cm (0.8 in) in diameter, appearing in a ring in the upper part of the plant. The fruits are red, oblong, persisting for a long time. Seeds are black, small.

Mammillaria seeds are small, dark brown or black, rounded or slightly oval. Germination of seeds under neat greenhouse conditions is usually around 50-80%.

Sowing is carried out in spring or year-round in the presence of stable lighting. A sterile fine-grained mineral substrate based on sifted cactus soil, fine sand, perlite, and mineral grit is used. Seeds are distributed over the surface, lightly pressed into the moist soil, and covered with a minimal layer of fine sand or left uncovered entirely. The sowing is moistened with a spray bottle using 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 in a propagator.

Germination is carried out under bright diffused lighting and a temperature of about 22-26 °C (72-79 °F), without direct overheating under the sun. The surface is maintained moderately moist but not wet; moistening is performed only with fine spraying. Sowings are ventilated daily, and condensation is removed, since stagnation of moisture is dangerous for mammillaria seedlings and quickly causes fungal damage.

The first seedlings may appear after 7-10 days; the usual germination period is 10-21 days, and the maximum possible period under temperature fluctuations or partial drying of the surface can extend up to 4-6 weeks. After seedlings appear, the cover is gradually opened, and the seedlings are kept under bright diffused light with careful moistening. Pricking out is carried out after the plants have noticeably strengthened and the first spines appear, usually no earlier than several months, with minimal root disturbance.

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For cultivation, the brightest possible location with several hours of direct sun per day is selected. South, southeast, and southwest windows are best suited, and supplemental lighting is recommended during overcast seasons. After a dark wintering or repotting, the plant is gradually accustomed to direct sun to prevent scorching 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 thermophilic and does not tolerate cold dampness. Wintering is kept bright, dry, and moderately cool, around 8-12 °C (46-54 °F), with nearly complete cessation of watering. At lower temperatures, wet substrate is particularly dangerous and can cause 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 reduced; in winter, the plant is kept almost completely dry. Getting water into the axils between tubercles is undesirable, especially in cool conditions and with weak ventilation.

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

Fertilizer 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 nutrition causes loose growth and reduces resistance to rot. Repotting is carried out in spring as the pot becomes root-bound; after repotting, the plant is kept without watering for several days. Pruning is not required, and separation of side offsets is possible only in well-grown specimens.