All cacti here are on 

sale

 

 Astrophytum is a genus of six species of cacti. These species are sometimes referred to as living rocks, though the term is also used for other genera, particularly Lithops (Aizoaceae). The generic name is derived from the Greek words άστρον (astron), meaning "star," and φυτόν (phyton), meaning "plant."



  the star of the cacti. 

Astrophytum is a genus of six 


species of cacti. The Common 


names: Sand Dollar Cactus, Sea 


Urchin Cactus, Star Peyote, 


Bishop's Cap Cactus, Bishop's 


Hat, Bishop's Mitre Cactus, 

 

Hood All a MONK'S but cacti 

You name your needs and we can provide them.  With an experienced staff working around the clock, you can be sure we will get the job done and get it done right.

Contact us now!

   Astrophytum myriostigma

 A. myriostigma is commonly grown as an ornamental plant in cactus collections. This plant has gained the Royal Horticultural Society's Award of Garden Merit.[1]

To obtain a blooming seedling Astrophytum myriostigma click here. You will get 20% off.

Family: Cactaceae (Cactus Family)

Scientific name: Astrophytum myriostigma Lem.

 Etymology: 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. 

Origin: Astrophytum myriostigma is a species of cactus native to the highlands of northeastern and central Mexico.

Conservation status: Listed in CITES appendix 2.

Habitat:

Common English Names:  Bishop's Cap Cactus, Bishop's Hat or Bishop's Miter Cactus) 

Synonyms: Echinocactus myriostigma, Astrophytum prismaticum, A. columnare, A. coahuilense, A. tulense, and A. nuda.   

  


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) A. myriostigma is commonly grown as an ornamental plant in cactus collections. This plant has gained the Royal Horticultural Society's Award of Garden Merit.[1] A. myriostigma is a spineless cactus defined by the presence of three to seven (usually five) pronounced vertical ribs which define the cactus' shape when young (the genus name "astrophytum", literally, "star plant", is derived from the resulting star-like shape). As the cactus ages, more ribs may be added and it becomes more cylindrical in shape, growing up to about 70-100 cm tall and 10-20 cm in diameter. The stem is often covered with whitish flecks.     

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.

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.        

Areoles: 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. 

Radial spines: Wanting.

Central spine(s): Wanting.

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. The cactus flowers in the spring or summer with one or more waxy flowers 4-6 cm diameter near its apex; the numerous petals are yellow, sometimes with an orange or red base. . Pollinated flowers develop into a hairy reddish fruit about 2-2.5 cm in diameter. 

Bloom time: 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.

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.

Seeds: Dark brown, shining, with a large depressed hilum, the margins being turned in.

Sun Exposure: Light shade to full sun, its color tends to richer and darker when grown in light shade.  

Recommended Temperature Zone: USDA: 9b-10

Frost Tolerance: Hardy to 20°F (-6°C) for short periods

Heat Tolerance:

Minimum Avg. Temperature: 50°F (10°C)

Watering Needs: Moderate water in summer. Needs dry winter rest.

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

Astrophytum myriostigma cultivar ONZUKA from my collection

Notes: This quite variable plant has been widely grown for years and is now available in several cultivated variety and several breeds do exist. The famous “Onzuka” is only one of these and though maybe the most beautiful, but a lot of other forms are represented in many collections.

Want to buy Astrophytum myriostigma
 Ø5 cm for $6.00. New price $3.80 Out of stock


 Astrophytum capricorne

 Astrophytum capricorne also known as the Goat's horn cactus has more spines than most Astrophytum species. Wikipedia

 Family: Cactaceae (Cactus Family)

Scientific name: Astrophytum capricorne (A. Dietrich) Britton & Rose 1922

Astrophytum capricorne was described at the year 1851 from Dr. Albert DIETRICH as Echinocatus capricornis. 

In 1922 BRITTON and ROSE recombined this genus to Astrophytum.

Etymology:

Origin: Northern Mexico (Coahuila) widespread in the

Chihuahuan Desert.

Conservation status: Listed in CITES appendix 2.

Habitat: The Capricorn covers a wide range in the north-east Mexico (mostly in the state of Coahuila) which can be outlined by a triangle formed by the cities of Monterrey, Monclova and Torreon

It grows in desert areas where rainfall is much lower than in the habitat of other species of Astrophytum.Neighboring rainfall of 250-350 mm / year (considering it is a desert when cumulative rainfall is below 200 mm / year) and even only 180 mm / year in the area of Cuatro Cinegas. 
It grows mainly on limestone stations, among rocks and thorny bushes. He appreciates including the protection of Agaves lechuguilla to develop the 1st year.

 Common English Names: Goat's Horns Cactus. The Goat's Horn (capricorne) is named for the characteristic shape of its long, curled spines.

Synonyms: Astrophytum capricorne var. capricorne, Echinocactus capricornis

 Description: Solitary globular or columnar cactus.

Stem: Although young plants are globular, they soon become ovoid, and eventually columnar up to 1.2 m tall, 10 (15) cm indiameter. The epidermis of is more or less covered with the typical white woolly flecks characteristic of the genus.

Roots:

Ribs: Usually 8.

Areoles: In vertical rows along each rib

Spines: 5 to 10 up to 7 cm long, Grey to brown wired, twisted, curved, flattened that look like the horn of a Capricorn. As plant ages spines get a bit more intense and messier, but relatively sparse, they are stiff but pliable and fragile, so, plant should be handled with care.

Radial spines:

Central spine(s):

Roots:

Flowers: The flowers are diurnal typically open in the morning and close just before the sunset. Sweet smelling 7.5 cm wide, yellow with a red center.

The throat and the base of the petals are red

Bloom time: Blooms in summer.

Fruit: Reddish covered with flattened spines, 2.5 cm in diameter.

Seeds:

Sun Exposure: Light shade to full sun.

Recommended Temperature Zone: USDA: 9-10

Frost Tolerance:

Heat Tolerance:

Minimum Avg. Temperature: 50°F (10°C)

Watering Needs: Moderate water in summer.

Cultivation: Although regarded as a choice and difficult plant in cultivation it is relatively easy to grow. Use mineral well permeable substratum (rot prone). Water sparingly from March till October and keep perfectly dry in winter at temperatures from 5 to 15 degrees centigrade but tolerates mild frost without a problem as do all the other common species of Astrophytum(hardy to -7°C for short periods). In the rest period no high atmospheric humidity!! 

Propagation: They can be propagated easily from seed.

Notes: Camouflage: The fine spines of this species are an optical artifice supporting the grass-mimicry to the surroundings.

Astrophytum capricorne and its varieties are very variable in their habit even in small areas. Plants vary in the amount of flock on the surface, in the number,  length, shape and color of the twisted spines, and in the size of the stems. And it is understandable that today we often have problems to decide to which population plants belong.

 Notes: This is the first species of Astrophytum which was discovered. 

It all started in 1827, when Thomas Coulter discovers an unknown plant in the state of Hidalgo in Mexico. He immediately sent 40 copies to Paris. In 1828, this plant is described by De Candolle as Echinocactus ornatus is the Astrophytum ornatum known today. 
The genus Astrophytum created by Charles Lemaire in 1839 following the discovery of A.
 myriostigma. 
But our Echinocactus ornatus, having changed names several times (E. holopterus, crooked, ghisbrechtii ...) not join the kind Astrophytum under its current name until the late 19th century, in 1896 under the initiative of Weber .
 Indeed, its silhouette different from other "cactus-star" has long been away from Astrophytum but Weber believes that the presence of flaking on the skin is also a major character in this genus. 
Then in
1937, in their Cactus Family, Brighton & Rose confirm and validate the name Astrophytum ornatum. 

Ornatum Astrophytum species is located furthest to the south, a hundred miles north of
Mexico in the states of Hidalgo and Queretaro. It also overflows slightly to the south of the state of San Luis Potosi and Guanajuato is. 
In fact, its range extended along the watershed of the Rio Moctezuma and its tributaries.
 Seed dispersal being carried by ants attracted by nutrients. 
It colonizes the steep slopes of the valleys and sunny but is absent plains where the soil is deep and fertile yet.
 
The annual rainfall is around
500 mm but mostly concentrated from June to September.

According to the canyons, there are populations that have evolved over time to different forms more or less columnar, flaking more or less developed, twisted shapes, spines more or less yellow and of varying lengths.Ornatum species remains fairly massive columnar taking a look older and whose adult size is often greater than 1m (up to 1.8 m). Flaking tends to be less developed when the old cactus plants sometimes give up almost naked (this change is not reflected ornatum our culture). 

The locations have been quite difficult to access protected species. However, the construction of a hydro-electric dam in the 90s has greatly reduced the population present on the slopes of Rio Moctezuma (and beautiful Echinocactus grusonii). 

In the area of Torre de Rio Blanca (at the boundary between the state of Queretaro and Guanajuato), there is a population of ornatum with a twisted shape, with spiral ribs. This form is not due to a lack of water as originally thought due to the very low rainfall in the area. This is a character that appears genetically stable. This population has been known since the mid 19th century and was known as Echinocactus crooked. It does not seem a variety is valid for this unusual, yet sometimes found among some producers ornatum v. espiralis with this strange twisted shape. 

There is another population near the Rio and Rio Amajaque Tula, with a more stocky with beautiful yellow spines, is the variety mirbelii. It seems that this is the only variety that is valid for the species ornatum. ( Information was taken from Astro-Web)

 Astrophytum caput-medusae

Photo was taken from cactus-art.biz 

When first appeared on the market the seeds were selling as much as 5 Euro per seed and young plants for 100 Euros.

Scientific name:  Astrophytum caput-medusae (Velazco & Nevarez) D. Hunt comb. nov. 2003

Published in: HUNT, D. Cactaceae Systematic Initiatives, 15(4):1-2; 5-6, 2003

Etymology: The genus name "Astrophytum" derives from the Greek words "aster (αστηρ)", meaning a "star" and"phyton (φυτον )", meaning  "plant". ( The Genus name implies: "star plant"). 

The species name "caput-medusae" derives from  the Latin word “caput” which means “head” and "Medusa (Μεδουσα)"  the Greek mythological woman whose blond hair was turned to snakes and whose stare turn objects to stone, was slain by Perseus. ( The specific name implies: "Medusa's head")

Origin: Mexico, Nuevo León (locality withheld)

Conservation status: Listed in CITES appendix 2.

Habitat: Grows among shrubs in the Matorral espinoso tamaulipeco(Tamaulipan thornscrub land) in shaded position.

Common English Names:

Synonyms: Digitostigma caput-medusae Velazco & Nevarez 2002

Description: Solitary or rarely clustered up to 19 of eight.

Stem:. Very reduced, shortly cylindrical, lacking ribs, with papyraceous  bristles covering thecollar and the stem  apex, the bristles probably originate from the basal rest of the tubercles, the colour of the bristles of tubercles is coffee whit reddish tones, the stem bristle of plants growing in habitat rarely exceed the ground level.

Tubercles: Cylindrical or occasionally triangular when young, of cartilaginous consistency, smooth, could appear similar in aspect to leaves, up to 190 mm in length and of 2 to 5 mm wide, some times the adaxial portion of the base of the tubercle  is cuneate Epidermis verrucose, glaucous-green, covered by stigmas (squamiform peltate trichomes) of a greyish-white colour, covering almost the totality of the epidermis towards the base of the the tubercle. 

Roots: Primary root fusiform, fleshy; secondary roots fibrous. The root is of the same dimension or slightly smaller of the aerial part.

Ribs:

Areoles: Dimorphic; the spiniferous one are terminals, circular or elliptical, with white wool; the floriferous one are located in the adaxial subterminal portion, separated from the spiniferous from 18 to 46 mm elliptical, with white wool, but noticeably larger than the spiniferous areoles.

Spines: 0 up to 4, generally persisting in old tubercles, of 1 to 3 mm in length, semi-erect, rigid, the base is whitish  with a dark-coffee apex.

Radial spines:

Central spine(s):

Flowers: Originates in the subterminal portion of the developing tubercles, not in the plantapex. The flowers are diurnal, yellow, with the base of the inner perianth segments orange coloured. Outer segments greenish yellow, The receptacular tube displays papyraceous,lanceolate  scales, with  terminal aristae and short white hairs in the axil; Lanceolate scales with white hairs in the axil are also presents in the pericarpel.

Bloom time: Mid Summer Late Summer/Early Fall

Fruit:. Green and fleshy when young, covered with lanceolate scales with wool in the axil, dry when ripe with irregular longitudinal dehiscence. 

Seeds:

Sun ExposureSun to Partial Shade

Recommended Temperature Zone: USDA Zone 9a: to -6.6 °C (20 °FUSDA Zone 9b: to -3.8 °C (25 °F); USDA Zone 10a: to -1.1 °C (30 °F); USDA Zone 10b: to 1.7 °C (35 °F)

Frost Tolerance:

Heat Tolerance:

Minimum Avg. Temperature:

Watering Needs: Average Water Needs; Water regularly; do not over water Suitable for growing in containers

Cultivation: The specific requirements of this new and very particular plant still need be investigated. 

In this two years we have done some preliminary observation on a very limited sample of seedlings:

 The plants grow very fast either grafted and on their own roots (possibly grafting is not required)

  • Grafted plants are very sensible to drought, waterlessness for a few day conduct (especially in summer) to a complete or partial loss of tubercle that dry in a few hours, this seems due to the very small proportion of the stem, and to the fact that the big tap root (a water storage organ) is not present, in fact the plants on their own roots are more stable and resistant. Anyway the tubercles are deciduous they easily dry and detach but are soon replaced by new one (a single tubercle can reach maturity in a few week)
  • Young seedlings seem to need some light watering in winter, no damages or rot has been evidenced for plants watered in winter.
  • They prefer a shaded or semi-shaded position as they live in habitat under shrubs.
  • All the few plant under observation stopped to grow at the end of August, beginning a complete winter dormant. The first sign of new growth appeared only on the month of march.
  • The plant are quite resistant to frost (during winter the green house temperatures varied from a minimum of 0° C at night to a maximum of 25° C during sunny days) no sign of damage has been signalized.

Propagation: From seed; direct sow after last frost. By grafting

Notes: Although not currently listed on the IUCN Red List of Threatened Species™, Astrophytum caput-medusae qualifies as ‘Critically Endangered’ based on IUCN assessment criteria. This newly described cactus is named after Medusa, the woman in Greek mythology whose hair was turned to snakes, in reference to this species’ long, thin, almost snake-like tubercles. 

Astrophytum caput-medusae is endemic to Mexico, where it is known from just a single location, and is undergoing a rapid decline. The species is highly sought-after by collectors, and as a consequence is under threat from illegal collection. In addition, the plants are often trampled by livestock, and its very limited range puts the species at particular risk of extinction. Very little is currently known about the populations of this newly discovered plant. The species would benefit from effective protection and conservation efforts at the site where it occurs, while off-site propagation measures have also been recommended.

 

Translate This Page

Astrophytum the star of the cacti All about cacti Cactus for sale

Genus Astrophytum the star of the cacti. Astrophytum is a genus of six species of cacti. The Common names: Sand Dollar Cactus, Star Peyote, Bishop's Cap Cactus, Bishop's Hat, Bishop's Mitre Cactus, All about cacti Cacti for sale

 Species:

1. Astrophytum asterias (Zucc.Lem. – Sand Dollar Cactus, Sea Urchin Cactus, Star Peyote

2. Astrophytum capricorne (A.Dietr.) Britton & Rose – Goat's Horn Cactus

3. Astrophytum caput-medusae D.R.Hunt

4. Astrophytum coahuilense (Møller) K.Kayser

5. Astrophytum myriostigma Lem. – Bishop's Cap Cactus, Bishop's Hat, Bishop's Mitre Cactus

6. Astrophytum ornatum (DC.) Britton & Rose – Monk's Hood

 Below is the detailed description of Astrophytum asterias

Astrophytum asterias is a species of cactus in the genus Astrophytum, and is native to small parts of Texas in the United States and Mexico. Common names include Sand Dollar Cactus, Sea Urchin Cactus, Star Cactus and Star Peyote.                                          

Family: Cactaceae (Cactus

Family)

Scientific name

Astrophytum asterias

(Zucc.) .

 Origin:  is native to small parts of Texas in the United States and Mexico. 

 Conservation status: Listed in CITES appendix 1

 . Habitat destruction has been, and remains, the major cause of the decline in this species; vast areas have been converted to agricultural use and road construction.[6] In Texas, mechanical and chemical bush clearing techniques together with the introduction of invasive grasses have had devastating effects.[6]

The U.S. Fish & Wildlife Service have drafted a Recovery Plan in an attempt to secure the future of this species.[6] The Recovery Plan highlights the need to protect existing populations, carry out research into possible new populations and to develop a formal conservation agreement between the United States and Mexico.[6]

 Habitat: Star cactus is native to the lower Rio Grande Valley of Texas in the United States[5][7] and the states of Nuevo León and Tamaulipas in Mexico,[2] to the east of the Sierra Madre Oriental mountain range.[4]

Previously more abundant, this species is today restricted to a single 200-acre site in Texas, where there are around 2,000 individuals,[6][8] and a few small sites in Tamaulipas.[9] Today this species is associated with thorn scrub, amongst rocky ground; it may have previously occupied richer, flat grasslands that have since been developed.[4] It has probably been extirpated from Nuevo León.[8]

 Common English Names: Sand Dollar Cactus, Sea Urchin Cactus, Star Cactus and Star Peyote.

Etymology: The generic  name"Astrophytum" derives from the Greek words "aster (αστηρ)", meaning a"star" and "phyton (φυτον)", meaning"plant". ( The Genus name implies:"star plant"). 
The specific name "
asterias" derives from the Greek name “aster (αστηρ)”that means “a star” an aster type plant*,  and the Greek suffix “ias (-ιας) ”meaning “like to, comparable, similar”  The specific name implies: "star like (like an aster)"  
The shell of a sea urchin

Astrophytum asterias Photo from my collection 

Astrophytum myriostigma          Etymology: 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. 

Origin: Astrophytum myriostigma is a species of cactus native to the highlands of northeastern and central Mexico

Common English Names:  Bishop's Cap Cactus, Bishop's Hat or Bishop's Miter Cactus)

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 Mithra

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.

Minimum Avg. Temperature: 50°F (10°C)

Watering Needs: Moderate water in summer. Needs dry winter rest.

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. 

Astrophytum is a very popular genus in spite of having only a few species. Astrophytum myriostigma is widely distributed across in northern and central Mexico mainly in the Chihauhaun desert. It is an extremely variable species and may varieries have been described.

Astrophytum myriostigma for sale

Ø5 cm for $6.00. New price $3.80 Out of stock

Common names: Bishop's Cap Cactus, Bishop's Hat or Bishop's Miter Cactus) is a species of a cactus native to the highlands of northeastern and central Mexico

Astrophytum ornatum 

Astrophytum ornatum is the largest Astrophytum species. It is a rugged plant resistant to root rot, and easy to grow in a well drained soil, and also the fastest of the Astrophytums. 
Photo of Astrophytum ornatum is from my collection

Astrophytum ornatum for sale

 Ø6 cm for $6.95. New price $5.00.

 Family: Cactaceae (Cactus Family)

Scientific name: Astrophytum ornatum (DC.) Weber
In: Britt & Rose, Cactaceae 3: 185. 1922

Origin: Astrophytum ornatum is the southern genus of Astrophytum. The habitats are at Hidalgo, Queretaro and Guanajuato in Mexico.

Conservation status: Listed in CITES appendix 2.

Habitat: Grows in wild canyons and limestone cliffs sometime on near vertical rockfaces

Common English Names: Star cactus , also known as Monk's Hood, ornamented bishop's cap

Synonyms: Echinocactus ornatus De Candolle

In: Mém. Mus. Hist. Nat. Paris 17:114 1928; Echinocactus mirbelii Lemaire
In: Cact. Aliq. Nov. 22. 1838; Echinocactus holopterus Miquel
In: Linnaea 12:2. 1838; Echinocactus tortus Scheidweiler
In: Bull. Acac. Sci. Brux. 5:493. 1838; Echinofossulocactus mirbelii Lawrence in Loudon In: Gard. Mag. 17:318. 1841; Echinocctus ghiesbrechtii Salm-dick
In: Allg. Gartenz.18:395. 1850; Echinopsis haageana Linke
In: Wochenschr. Gartn. Chron. 1873:983. 1873; Echinocactus haageanus Rümpler In Förster In: Handb. Cact. ed. 2 469. 1885.; Echinocactus ornatus glabrescens Shumann In: Gesamtb. Kakteen 324. 1898A

 The Astrophytum ornatum is the largest and easiest to grow and also the fastest of the Astrophytums. Spherical when young to columnar when mature, some specimen develop nice twists with age.

Ribs have characteristic cross bands of wooly scales.

Description: A. ornatum is a shortly columnar cactus appearing star-shaped from above, with white cross bands of wooly scales. It appears to be a very variable species especially for the density and distribution of white scales. It is the largest and easiest to grow and also the fastest of the Astrophytums. It is also generally more heavily spined than other Astrophytums.

Stem: he stem is solitary, globose when young , cylindric with age, 30 to 120 cm (or more) high, 15-30 cm across, greyish-green to dark-green with more or less dense white or yellow wooly flakes in bands forming an ornate pattern.

Ribs: It has 5 to 10 (generally 8) straight or frequently spiralling, rather prominent, strongly compressed, more or less sinuate and crenate .

Areoles: 1 to 5 cm apart, at first yellowish-white felted, later grabrescent.

Radial spines: 5-11 stout, 2-4 cm long usually straight, subulated or ± laterally compressed, amber yellow, later brown and finally grey

Central spine(s): usually 1 rather larger.

Flowers: At apex, large, lemon-yelllow 7-12 cm broad, inner perianth segments broadly oblong, with a broad, more or less serrated apex, tube short woolly, scale on ovary, dark and very narrow.

Bloom time: The Astrophytum ornatum blooms in summer. The flowers (6-8 cm wide) are pale yellow with bright silken sheen and scented.

Recommended Temperature Zone: USDA: 9b-10

Frost Tolerance: Hardy to 20° F (-6°C)

Minimum Avg. Temperature: 50°F (10°C)

Heat Tolerance: Excellent in Phoenix in summer

Watering Needs: Moderate water in summer. Allow the soil to dry before watering again. Do not water in winter.

Cultivation: This cactus is pretty cold hardy and can survive to -10° C (if kept dry).  It needs to be at least 15 cm tall to bloom . This might take no less than seven years or more depending on the length of the growing period in the local climatic conditions. In the rest period no high atmospheric humidity!! Sun Exposure: Light shade to full sun.

This Astrophytum is the easiest to grow and also the fastest. It responds well to half strength fertilizer in summer. To make sure that the fertilizer doesn't encourage growth instead of blossom, it might be better to wait until the flower buds start forming before using fertilizer.

Propagation: They can be propagated easily from seeds.

Seed Collecting: Allow unblemished fruit to ripen; clean and dry seeds Unblemished fruit must be significantly overripe before harvesting seed; clean and dry seeds.

Properly cleaned, seed can be successfully stored

Astrophytum coahuilense (H. Möller) Kayser  Astrophytum coahuilense was dercribed from Dr. Heinrich MÖLLER at the year 1927 as Echinocactus myriostigma subspecies coahuilense. 

Regrouping some times later from Dr. KAYSER to Astrophytum coahuilense.
The habitus of the genus looks like Astrophytum myriostigma. But if we view the fruit, flowers and woolly flecks so the differences between the to genus become visible.

Origin: South-western Coahuila and Durante (Ciudad Lerdo, Sierra Baicuco, western Sierra Parras and southern of this line up to the Sierra of El Numero)

Description: Astrophytum coahuilense with five ribs, has a surprising similarity to A. myriostigma. However, it is different in all characteristics regarding flower, fruit, seed and embryo which looks like in all details to Astrophytum capricorne. The differences into flower, fruit, seed and embryo and flecks are constant and permit in any case to distinguish Astrophytum coahuilense without problems from A. myriostigma. 

 

Astrophytum coahuilense. Photo from my collection 

Nude plants as in the case of Astrophytum myriostigma are unknown. 
It looks like the bishop's cap (A. myriostigma), but softer, more grey flecksthat cover the plant even more than with the myriostigma.  The flowers are yellow with a characteristic red throat, although can appear pure red or very seldom pure yellow. In the fruit which is red till olive-green coloured and basal opening are up to 200 seeds, similar as in the case of Astrophytum capricorne. This plant is more related to the Asterias/capricorne group than the myriostigma.
A. coahuilense and A. myriostigma when cross are fruitless: they are (usually) sterile by each other.

Stem:. It is a green plant, boneless white dot, three to eight ribs pronounced. Is cylindrical, reaching a height of 70-100cm and a diameter of 10-20cm. 

It is a globular cactus, with five ribs well marked and angular, his skin is dark green, but is completely covered with white scales giving a spongy appearance, allowing you to blend where it grows among limestone.

With age it becomes more cylindrical, reaching a height of 50cm and 10cm wide, although data have been reported 65cm in length and 20cm in diameter.

Flowers: Yellow with red throat, blooms in spring and summer. The flowers emerge from the apex of the plant, from 2 to 3 years old, its size can be about 9cm in diameter and are yellow

Bloom time:. blooms in spring and summer

Fruit:. ripe fruit at 26 days of leaving the apex pollinate the flower as Astrophytum Capricorne and expelling tens of seeds (up to 200).

Cultivation: is not too difficult in a greenhouse, although grows quite slowly. The plants need  a loose well-drained  mineral soil. They need a good amount of light. Watering can be done weekly during summertime, if the weather is sunny enough, with a little fertilizer added. Kept this way, plants will show a healthy, although slow growth. They are frost hardy to -4° (-10°) C

Propagation: By seeds, remembering that  seedlings dislike strong light and dry conditions  and need to be repotted frequently. Eventually, as they become mature, they attain a maximum size of 8-10 cm (20) cm. However, old plants become senile and have a tendency to succumb to disease and a weak root system. At this stage, as is well known, they diesuddenly. So, after they reach 10 cm in diameter grow them slowly, and adopt a new repotting period, using intervals of every 2 - 3 years. Additionally grow them under drier conditions or with stronger sunlight. But plants are often grafted to accelerate growth as they would generally take at least a five years to reach maturity on their own, but the grafted plants are typical rather tall growing, compared with plants on their own roots that are usually more flat to the ground.