MAMMILLARIA: NIPPLE CACTUS
How to Grow and Propagate
Tender succulent plants, chiefly natives of the southwestern United States and Mexico, which belong to the Cactus family, Cactaceae. This is a very large genus, consisting of between two and three hundred kinds; they vary in height from 1-12 in. and mostly consist of a single thick, fleshy stem, surrounded by closely set tubercles (fleshy lumps) which are crowned with hairs or spines. The flowers, which are produced principally near the apex of the stems, are tubular at the base but the numerous petals spread out at the top into a star-shaped formation. They measure up to 2 in. in diameter and are purple, pink, red, yellow or white. The flowers are often succeeded by scarlet, berry-like fruits, which are very attractive.
Plants Without Leaves. All Mamuiillarias arc devoid of leaves and have a thick outer skin which enables these plants to live in dry, barren climates where most other plants cannot exist, because transpiration (giving off water) is reduced to a minimum. During rainy periods Mammillarias are capable of storing water, which is utilized during periods of drought. The name Mammiliaria is derived from mam ilia,' a nipple, and alludes to the small tubercles. Many of the species previously included in this genus are now referred to Coryphantha.
For Warm Greenhouse or Room Window, These plants can be grown in a sunny greenhouse or window, where the winter temperature does not fall below 55 degrees. They require a compost of two parts sandy loam ancl one part of equal portions of sand and crushed bricks. The pots, which should be just large enough to hold them, are filled to one third their capacity with crocks. These are covcred with leaves or moss to prevent the compost from washing into the drainage. Repotting is best clone in March or April, when new growth is beginning. The plants are knocked out of the pots, and the crocks and any loose soil removed with a pointed stick; they are then set in the new pots and the compost is made firm.
Repotting is not necessary every year; once every three or four years is usually sufficient. After potting, the plants arc placed on a sunny shelf or bench and no water is given to the soil until it becomes quite dry. A light syringing twice daily is beneficial as it keeps down red spider mites and encourages new growth.
Summer and Winter Management, When the soil becomes quite dry, it is thoroughly saturated, and subsequently, is kept moist throughout the summer. When growth has finished, in July or August, less water is given and the plants are exposed to the maximum amount of sunlight to ensure the production of flowers. From October until April very little water is required, sufficient only being given to prevent the stems from shriveling.
Taking Cuttings. The tops of the stems, or side branches if they are available, are cut off and laid in the sun for a few hours to enable a skin to form over the cuts. This prevents them from decaying when inserted in the soil. They are planted in sand, and not watered until the soil becomes quite dry. This treatment is continued until roots have formed, when they are potted separately in pots just large enough to hold them.
Raising Seedlings. Seeds may be sown during spring or summer, in pots of sandy soil. The seed pots are well drained and the seeds scattered thinly on the surface of the compost. They are lightly covered with finely sifted soil, the soil is moistened and a pane of glass is laid over the pot. The seed pot is set in a warm greenhouse or sunny window until germination takes place. The glass is then removed and the seedlings are exposed to full light and air. Sometimes germination is very irregular, but it is not wise to leave the glass on the pot once the majority of the seedlings are through. If some of them are up long in advance of the others, they may be pricked off into another pot, and the seed pot re-covered with the pane of glass. The transplanted seedlings must not be disturbed until they have made sufficient roots to fill small pots.
The seedlings of Mammillaria are very interesting to watch in their development. They appear first as little globular masses of green tissue. These are in reality little bundles of food-bearing cells which supply nourishment to the young plants. The growing point or shoot bud is at the tip of the globular structure, and, as this elongates, the “bag of food” is gradually absorbed by the developing plant.
The chief kinds are M. applanata, white tinged with red; M. barbata, rose-pink; M. Blossfeldiana, carmine; M. bocasana, red; M. compressa, purple; M. dealbata, carmine; M. echinaria, yellow; M. elongata, white; M. fragilis, Thimble Cactus, cream-colored; M. melanocentra, pink; M. spinossima', red; M. Pringlei, deep red; M. prolifera, yellow; M. pygmaea, cream; M. rhodantha, pink; and M. multiceps, yellowish salmon.