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Astrophytum myriostigma
The name Astrophytum comes from the Greek word for star plant.
These beautiful plants are globe shaped and are speckled with white
scales and flecks. As it ages, the plant becomes columnar.
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Description: A. myriostigma (many dotted) is a spineless
plant, usually solitary or with very few basal branches. A transverse
section of the stem reveal a perfect star shaped form (like the common
star-fish) giving the plant the appearance of a bishop's mitre (hence
the common name Bishop's cap)
Stem: Globular to cylindric up to 60(-100) cm tall (but usually
about 150 cm tall) and 10-20 cm in diameter, bright green, covered with
many minute white hairy scales that give it a characteristic chalk-white
or silvery-grey appearance, but sometime naked. The scales are composed
of very fine interwoven hairs, which, under a microscope, are very
pretty object.
Roots: Fine, fibrous.
Areoles: Closed together
Spines: Wanting.
Ribs: Usually 5, sometimes 4(or 3) that increase to eight or more
with age ( rarely even 10), vertical, regular, deep, prominent, very
broad and acute.
Flowers: Funnelform, 4-7 cm long glossy yellow and sweet scented
from the areole at the tip of the stem on mature plant. Outer perianth
segments narrow, with brown scarious tips. Inner perianth segments
numerous, oblong yellow with a silky shine. Scales on ovary tube
scaroious, imbricated, very narrow often bristly tipped, with long wool
in their axil.
Blooming season: Flowers appear intermittently throughout the
warm months from April to September. Plants may take up to six years to
flower.
Fruit: 2-2.5 cm in diameter, greenish to tannish-red Covered with
brown, overlapping scales, with long wool in their axil.
Seeds: Dark brown, shining, with a large depressed hilum, the
margins being turned in.
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The
fruit of A. myriostigma (above) is
very
hairy,
dehisces
apically and has a
greenish inner colour, it is very
different
from the fruit of
A. coahuilense (below)
which is pinkish
and opens
basally.
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Photo
and © copyright by
Andrea
B. (Bologna, Italy)
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Old plant Apex.
The areoles in the older plants are quite different from those
of juvenile specimens. They are large, very woolly, often
brownish/reddish (but variable in colour from white/ yellowish to
tan/black) and showy. |

The flowers are silky yellow (never red throated) |

Areoles |
Cultivation: Although regarded as a choice and difficult plant in cultivation it is
relatively easy to grow. It is sometime seen as a grafted plant but grows very
well on its own roots too. Use mineral well
permeable substratum with little organic matter (peat, humus). The
Astrophytum myriostigma grows much faster with a low nitrogen content
fertilizer in spring and summer. Water
sparingly from
March till October, the thin, fibrous roots suffer if there is
humidity, therefore the plant should be watered only when the
surrounding terrain is dry. Keep dry as soon as the temperature starts
dropping in October and keep it perfectly dry in
winter
at temperatures from 5 to 15 degrees centigrade.
(but it is
Hardy to -7°C for short periods) Although it is one of the
easier Astrophytum to grow, they tend to rot at that time of the year,
if kept wet. In
the rest period no high atmospheric humidity!!
Sun Exposure:
Light shade to full sun, its colour tends to richer and darker
when grown in light shade.
Propagation: Almost exclusively by seed. Plants are sometimes
grafted onto column-shaped cacti. Cutting scions from a flourishing
plant is almost a crime because the scions do not root easily.
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This quite
variable plant has been widely grown for years and is now available in
several cultivated variety and several breeds do exist. The famouse
“Onzuka” is only one of these and though maybe the most beautiful, but
a lot of other forms are represented in many collections.
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A. myriostigma cv ONZUKA "tricostatum"
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A. miriostigma "nudum"
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A. myriostigma cv. KIKKO "nudum" |

A. myriostigma "quadricostatum" round type
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Family:
Cactaceae (Cactus
Family)
Scientific name:
Astrophytum myriostigma Lemaire
Original description: Cactacearum Genera nova Speciesque novae et
omnium in Horto Monvillano cultarum: 4-6 1839
Origin:
Highlands of central and northern Mexico
Conservation status: Listed in
CITES appendix 2.
Synonyms:
- Echinocactus myriostigma
(Lem.) Salm-Dick CACT. hort. hort. Dyck. Cult., 22, 1841
Heterotypic synonyms:
- Cereus calicoche
Galeotti ex Scheidweiler
In: Bull. Cereus calicoche
Galeotti in Scheidweiler, Bull. Acad. Acad. Sci. Sci.. Bruxelles, 6 :
88, 1839 Bruxelles, 6: 88, 1839
- Astrophytum prismaticum
Lemaire
In: Cactées 50. 1868a
- Astrophytum coahuilense
(H.Moeller) K.Kayser 1932
- Astrophytum columnare
(K. Schum.) Sadovsky & Schütz 1979
- Astrophytum myriostigma f. nudum
(R.Meyer) Krainz 1967
- Astrophytum myriostigma f.
quadricostatum (H.Moeller) Krainz 1967
- Astrophytum myriostigma f.
tulense (K.Kayser) Krainz 1967
- Astrophytum myriostigma subsp.
coahuilense (H.Moeller) Y.Okumura 1933
- Astrophytum myriostigma subsp.
potosinum
- Astrophytum myriostigma subsp.
tulense K. Kayser 1932
- Astrophytum myriostigma var.
coahuilense (H.Moeller) Y. Ito, 1952
- Astrophytum myriostigma var.
columnaris (K. Schum.) Y. Ito, 1952
- Astrophytum myriostigma var.
nudum (R.Meyer) Y. Ito, 1952
- Astrophytum myriostigma var.
quadricostatum (H.Moeller) Y. Ito, 1952
- Astrophytum tulense (K.Kayser)
Sadovsky & Schütz 1979
- Echinocactus myriostigma subsp.
coahuilensis H. Moeller 1927
- Echinocactus myriostigma subsp.
potosina
- Echinocactus myriostigma subsp.
quadricostatum
- Echinocactus myriostigma var.
columnaris K. Schum., 1898
- Echinocactus myriostigma var.
nuda R. Meyer, 1912
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A popular Japanese cultivar "Onzuka"

It adopts a spherical form with a crackled grey surface that
resembles the surrounding rocks this help it to camouflage with
background.

Forma
variegata |

A mature specimen
Photo of conspecific
taxa, varieties, forms and cultivars of Astrophytum myriostigma:
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