cause of cresting: The cause of cresting is not fully explained.
as to why some plants grow in this unusual form.
speculate that it is a genetic mutation. Others say it is the result of
a strike of
lightning or freeze damage, but whatever the stimulus, the growth
point of the stem has switched from a geometric point, to a line, which
folds and undulates as the crest expands. Though these crested
M. longimamma are very rare, cresting occurs naturally, and can be
encountered in many other cactus species.
Description: This is a very
nice crested Mammillaria, easily recognizable for its long soft
fresh green tubercle.
Stem: Very fat (quite large for a crested plant ( 8 to 10 cm
thick) it can form in age a large convoluted mound.
Spines: 8 to 10 all quite similar in shape, thin, needle
like, yellow to amber coloured up to 20 mm long, of which one central
spine slightly longer (up to 25 mm long)
Flowers: Very large for this genus, 4-6 cm. long, 4.5-6 cm. wide
with bright yellow petals in May-July.
Cultivation: The grafted
plants are easy to grow and will form a large brain-like mounds
with age. Watering during the active growing season (spring and
summer); this will encourage steady growth, and prevent the large
tubercles from becoming flabby.
The plants on their own roots
has fairly large tuberose roots, and should be kept in a deep pot with a
very draining mineral substrate. But be particularly careful with
watering, which all thick rooted species require (rot sensitive). Keep
dry during the winter rest, when the plant may pull near the surface of
the potting mix.
Propagation: Grafting or