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Accepted Scientific Name: Astrophytum ornatum (DC.) F.A.C.Weber in Bois
Dict. Hort. [Bois] 1: 467. 1896 Bois
Origin and Habitat: Garden origin (Nursery produced cultivar)
Astrophytum ornatum (DC.) F.A.C.Weber in Bois
Dict. Hort. [Bois] 1: 467. 1896
- Astrophytum ornatum (DC.) F.A.C.Weber in Bois
- Astrophytum ornatum f. aurea hort.
- Astrophytum ornatum f. cristatum hort.
- Astrophytum ornatum f. dichotomicum hort.
- Astrophytum ornatum var. glabrescens (F.A.C.Weber) Y.Okomura
- Astrophytum glabrescens F.A.C.Weber
- Astrophytum ornatum var. glabrescens (F.A.C.Weber) Frič
- Astrophytum ornatum f. glabrescens (F.A.C.Weber) Krainz in Krainz
- Astrophytum ornatum f. nuda hort.
- Astrophytum ornatum subvar. glabrescens (F.A.C.Weber) Backeb.
- Astrophytum ornatum var. virens Schütz & Z.Fleisch.
- Echinocactus ornatus var. glabrescens F.A.C.Weber in Bois
- Astrophytum ornatum var. glabrescens f. variegata hort.
- Astrophytum ornatum Metztitlan, Hidalgo, Mexico.
- Astrophytum ornatum var. mirbelii (Lem.) Frič
- Astrophytum ornatum f. mirbelii (Lem.) Krainz in Krainz
- Echinocactus mierbelii Lem.
- Echinocactus ornatus var. mirbelii (Lem.) Croucher
- Echinofossulocactus mirbelii (Lem.) Lawr.
- Astrophytum ornatum var. niveum Schütz & Z.Fleisch.
- Astrophytum ornatum cv. Fukuryu Hania
- Astrophytum ornatum cv. Hania
- Astrophytum ornatum cv. Kikko
- Astrophytum ornatum cv. Spiral
Description: Astrophytum ornatum (a.k.a. Ornamented Bishop's Cap ) is a shortly columnar cactus appearing star-shaped from above, with white cross bands of woolly scales less than pinhead-sized.
Forma aurea or aurata (yellow form): The schizochromic form (Astrophytum ornatum f. aurea) has pale yellow stems due to the absence (or reduced production) of chlorophyll pigments: every other pigment is present at normal levels, the dominant green colouration is lost, but will still more than likely have normal other pigments that give the yellow overall appearance of the stem. This form with yellow stems is very attractive and highly prized. This schizochromic form is almost always seen grafted on stronger columnar species, and cannot can be grown on its own roots. However some clones have enough chlorophyll in their tissues and can be grown on they own roots too, but very slow growing.
Stem: The stem is solitary, globose when young, cylindric with age, but much smaller and thinner than the standard green form and rarely more than 10 cm tall, pale to dark yellow, with more or less dense white woolly 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 2 cm apart, at first yellowish-white felted, later grabrescent.
Radial spines: 5-11 , up to 2 cm long usually straight, subulated or ± laterally compressed, amber yellow, later brown and finally grey.
Central spine: usually 1 rather larger.
Flowers: At apex, large, lemon-yellow 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.
Subspecies, varieties, forms and cultivars of plants belonging to the Astrophytum ornatum group
- Astrophytum ornatum (DC.) F.A.C.Weber in Bois: It is the largest 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.
- Astrophytum ornatum f. aurea hort.: Mutant completely lacking chlorophyll pigment. The result is a completely yellow plant.
- Astrophytum ornatum f. cristatum hort.: Crested form.
- Astrophytum ornatum f. dichotomicum hort.: Time by time a plant dichotomize and the stem apex splits in two or more growing point.
- Astrophytum ornatum var. glabrescens (F.A.C.Weber) Y.Okomura: The stem is smooth, dark green without (or with very few) wooly flakes.
- Astrophytum ornatum var. glabrescens f. variegata hort.: has sectors, patches or stripes with distinct shades of yellow or orange.
- Astrophytum ornatum Metztitlan, Hidalgo, Mexico.: The plant from Meztitlan are characteristically covered in dense, evenly spaced white flecks and are easily tell apart from standard ornatums.
- Astrophytum ornatum var. mirbelii (Lem.) Frič: It is recognizable for its canary yellow spines. The stem is stout and very white and take a long time in the transition to the adult form. it is considered by many the most beautiful variety of the species.
- Astrophytum ornatum var. niveum Schütz & Z.Fleisch.
- Astrophytum ornatum cv. Fukuryu Hania: ribs irregularly supplied with raised ridges and white linear, woolly areoles. It appears to be a very variable.
- Astrophytum ornatum cv. Hania: The woolly areoles on the ribs have a felty line between them so it seems like the areoles are connected with each other.
- Astrophytum ornatum cv. Kikko: The stem is entirely split in tubercles, and could be a mutation much like the Astrophytum myriostigma cv. Lotusland, but much larger and robust with longer tubercles.
- Astrophytum ornatum cv. Spiral: It is a tiny finger-sized cultivars with very particular spiral ribs.
Notes: Variegation, albinism & schizochromism.
Variegation: A variegated plant has sectors, patches or stripes with two or more different colours, even distinct shades of green. Plants with variegated stems or leaves are often attractive and highly prized. In most species the stems or leaves are normally green, and variegated epidermis is an uncommon mutation, termed a chimera. A chimeral variegation is due to losing the ability to produce chlorophyll in some of the plant’s tissue, so that this tissue is no longer green. Tissues lacking chlorophyll are usually white or pale yellow coloured (due to carotenoid pigments) or red (due to betalain or anthocyanin pigments) contrasting with the normal green tissue. There are several forms of variegation, depending on the tissues that have been affected. The variegation in some forms is unstable. The extent and nature of the variegation can vary, and sometimes the plant will return to the green form. In others it is stable and does not change under normal conditions. Because the variegation is due to the presence of two kinds of plant tissue, propagating the plant must be by a vegetative method of propagation that preserves both types of tissue in relation to each other.
Albinism: Every once in a while a plant exhibits albinism (completely lacking chlorophyll pigment). This means that its tissue is unable to carry out photosynthesis. The result is a completely cream-white plant. This plant will be weaker than a green plant, and albinism is generally a fatal trait (it can't produce its own food and it's not getting it from anywhere else). Without chlorophyll, the albino plant has no way to manufacture the food needed for survival and growth to maturity. This implies that these plants cannot survive on their own roots, and necessitate being grafted on a normal green plant that provides food. Some of these albino plants are indeed very popular, and sought after by collectors.
Schizochromism: The yellow or red appearance of some plants is more precisely caused by another aberration called "schizochromism". Here, though, the specific green pigment (chlorophyll) is missing: every other pigment is present at normal levels. The dominant green colouration is lost, but the plant will still more than likely have normal other pigments that give the yellow overall appearance of stems and the red colouration of spines.
Bibliography: Major references and further lectures
1) James Cullen, Sabina G. Knees, H. Suzanne Cubey “The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass” Cambridge University Press, 11/Aug./2011
2) David Hunt, Nigel Taylor “The New Cactus Lexicon” DH Books, 2006
3) Edward F. Anderson “The Cactus Family” Timber Press, 2001
Cultivation and Propagation: Variegated cacti are regarded as choice and difficult in cultivation, but despite that many of them are relatively easy to grow. But be aware that they cannot tolerate prolonged exposure to direct sun light (especially during the hottest summer days), so grow them in half-shade or under filtered sun. They are sometime seen as grafted plants, but many grow well on their own roots, too.
On the contrary, the albinos can survive only if grafted on a strong green base.
Use mineral well-permeable substratum with little organic matter (peat, humus). Water sparingly from March till October and keep perfectly dry in winter at temperatures from 5 to 15 degrees centigrade. (In general these plants are more tender and cannot endure freezing temperatures ) In the rest period no high atmospheric humidity!!
Propagation: Almost usually by seed. Plants are often grafted onto column-shaped cacti.
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