Mammilarias are a wondeful group of plants for the collector. They are extremely diverse in their habits, whilst retaining a unifying globular to short-cylindrical body form. Their most endearing feature is the way that their body is formed from more or less prominent tubercles which are arranged in a spiralling pattern.
The name Mammilaria comes from the Greek word for breast, and that is easy to understand when some of these plants are examined. The growing point of these cacti is divided, so that flowers and fruit are produced from between the bumps, or tubercles (normally the flower arises from the tip of the bump - known properly as the areole) together with a variable amount of hair, which are just very thin spines. The tip of the tubercle carries the main spination, which tends to comprise a numerous, radiating set with a small number of stronger centrals which may be hooked or greatly extended. Individual flowers are usually quite small, but are produced in quite large numbers and in succession. Sometimes a complete circle may open simultaneously to form a garland around the crown. If the flowers are pollinated successfully the resulting fruits can be very decorative, especially the elongated red berries of some varieties. Remember that most cacti are self-sterile, so you will need at least two genetically distinct individuals, not clones.
|M. microhelia is a remarkably fine-looking plant with its spines arranged in a pale-coloured halo around the tip of each tubercle. The central spines are a dark chestnut brown, which makes a good contrast. This plant remains fairly small, usually solitary and will produce a short column in 6 or 8 years. The pale, greenish-yellow flowers are borne early in the year, and will be produced on quite young plants. There is no finer sight in early March than the swelling buds pushing aside the dense spines and anouncing that Spring is here again. In my collection this is always one of the first to bloom each year.||M. bocasana is one of the easiest plants to grow and flower in a beginner's collection. The fluffy appearance is due to a mass of interlocking hairs which grow from between the tubercles. It is not particularly cuddly, as the central spines are neatly hooked, and is easily caught on a stray finger or sleeve. With age the plants will cluster, and eventually form a round, hairy pillow. The flowers are variously cream with a dark pink stripe, to all-pink and will appear over a period of many weeks. If possible, obtain two plants grown separately from seed. Then you will be able to pollinate the flowers and see these extraordinary pink fruits which erupt in a remarkably short space of time in the late Summer.||M. densispina usually wins the race to open the first flower of the season. This attractive, spiny ball remains solitary and grows to no great size in old age. The yellow flowers do not open wide, but are produced in profusion in the early Spring. Unusually, the flowers are self-fertile, so in the Summer there will be a crop of fat, greenish berries between the close-packed spines. These will dry up to make a dark, persistent seed-pod. As the seed is so freely produced, it makes an ideal subject for first attempts at seed-raising. Break up the dry pod carefully and separate the brown seeds from the tough husk. In my greenhouse, self-sown seed from old fruits germinates in the pot with the parents, providing a ready supply of new plants to prick out after a year or two.|