Euphorbia milii

Crown of thorns (Euphorbia milii )

The crown of thorns (Euphorbia milii, Syn: .. Euphorbia bojeri Hook, Euphorbia splendens Boii ex Hook, Euphorbia var splendens bojeri ( Hook. ) Leandri ) is a species in the genus Euphorbia (Euphorbia ) from the family of the spurge family ( Euphorbiaceae ).

Origin of the name

The Christ's Thorn received his German name because its thorny branches reminiscent of the biblical Jesus' crown of thorns. Since the species was imported but only in the 19th century from Madagascar and Madagascar at the time around was practically inaccessible, sometimes still suspected use is completely ruled out as a biblical crown of thorns.

The scientific name commemorates Baron Pierre -Bernard Milius (1773-1829), the French governor of the island of Bourbon (now Réunion) was. This 1821 sent three plants of the then-unknown type at the Botanical Garden of Bordeaux. From these same plants described and published Desmoulins 1826, the way he named in honor of Milius.

Description and distribution of the natural kind

He is a succulent, thorny and leafy shrub. Within the genus Euphorbia he is one with more than 50 other species in the subgenus Euphorbia, section Goniostema in which bear the species paired and most strikingly colored bracts under the cyathia that mimic the missing petals of the flowers greatly reduced. These special bracts are called " cyathophylls ". Like all euphorbias also contains the crown of thorns a toxic and irritating milky sap.

Varieties

Euphorbia milii Desmoul. var milii grows in western Madagascar and is richly branched shrubs that reach heights of growth of up to 1.5 meters. The branches have a diameter of up to 1 cm. The dark green, lance-shaped leaves are up to 4 cm long and 2 cm wide. The stipule - thorns ( Stipulen ) are twisted around the blade root and are 1-2 cm long. The inflorescence stems are two to three times dichotomously and carry small cyathia with outstretched, about 6 × 8 mm ², mostly red (rarely yellow ) cyathophylls.

Euphorbia milii var bevilaniensis ( Croizat ) Ursch & Léandri 1955 grows in southern Madagascar ( between Anosy and Adroy District ) on gneiss rocks in forests and deviates by inverted triangular leaves, shoots with about 5 mm in diameter and up to 1 cm long thorns.
Euphorbia milii var hislopii ( NEBr. ) Ursch & Léandri 1955 grows in central Madagascar and is only in culture ( as a hedge plant ) is known. She is a total coarse and robust, forming to 2 m tall shrubs, up to 2 cm thick shoots, up to 15 × 5 cm ² large leaves and up to six times forked Infloreszenzstiele.
Euphorbia milii var Imperatae ( Léandri ) Ursch & Leandri 1955 grows in coastal forests of eastern Madagascar and differs by only 50 cm large shrubs with only 5 mm thick branches, ovate, to 10 × 7 cm ² large leaves and only one to bifurcate, short Infloreszenzstiele.
Euphorbia milii var longifolia Rauh 1967 grows in central Madagascar on granite rocks and differs mainly by basal branching, sagging, up to 2 cm thick branches, linealische, to 20 × 1 cm ² large leaves and yellow cyathophylls.
Euphorbia milii var Roseana Marn. -lap. 1962 grows in the central to southern Madagascar ( at Sakaraha ) in forests and deviates by fairly upright branches, lanceolate, to 9 × 2.5 cm ² large leaves, bifurcate Infloreszenzstiele and whitish yellow cyathophylls.
Euphorbia milii var splendens ( Bojer ex Hook. ) Ursch & Léandri 1955 grows in Madagascar and real -center deviates by up to 2 m tall shrubs, bright green leaves, numerous, basal compressed spines and sometimes yellow cyathophylls.
Euphorbia milii var tananarivae ( Leandri ) Ursch & Léandri 1955 grows in central Madagascar and is only in culture ( as a hedge plant ) is known. They differ because of large shrubs up to 2 m, to 3 cm thick branches and up to 8 × 10 mm ², yellow, red -rimmed cyathophylls.
Euphorbia milii var tenuispina Rauh & Razaf. 1991 grows in southern Madagascar ( in the mountains around Ihosy and Isalo ) and differs by a thickened at the base, bulbous base and very slender spines.
Euphorbia milii var tulearensis Ursch & Léandri 1955 grows in south-western Madagascar ( at Toliara ) and differs by smaller, up to 1 cm long thorns and bright red cyathophylls.
Euphorbia milii var Vulcanii ( Leandri ) Ursch & Léandri 1955 grows in the central to southern Madagascar ( between Betafo and Ambatofinandrahana ) and differs by bluish-green, to 20 × 5 cm ² large leaves, about 1 cm long, arranged in ten rows of thorns and long, four times bifurcated Infloreszenzstiele.

Almost all varieties are only available in stores. Only E. milii var splendens is also offered in flower shops and hardware stores. All varieties can be kept as house plants and require a very bright location without too much direct sun all year and temperatures above about 12 to 15 ° C. Suitable locations are looking for example in southern directions windowsills. A summery outdoor stay, eg in the light shade of a tree, leading to growing plants stocky and powerfully designed colored cyathophylls. All varieties grow only seasonal and need in our winter dry rest. During this time, the only cast so weak that the root ball dry out not completely, the plant lose almost all leaves. Healthy plants can withstand a completely dry winter, then in spring but have teething problems when they again only need to form new roots. Are plant by poured over the winter, they tend to etiolation, are susceptible to disease and sometimes rotten away quickly. Animal pests are extremely rare because of the poisonous milky juice. In high humidity mildew can occur.

Hybrids

Most cultivated varieties commercially available hybrids of Euphorbia milii go on with Euphorbia lophogona Lam. Back in 1788.

Hybrids of E. milii and E. lophogona often arise randomly, when the plants are in collections close together. First reports of such hybrids are from Franklin Crosby from Malibu, California, USA (1960) and Harry Hall from Kirstenbosch, South Africa ( 1961). These known as ' California hybrids ' varieties bear interrupted spike rows that represent a compromise between the paired spines of E. milii and the continuous spike rows of E. lophogona.

The Werner Rauh, a professor at the University of Heidelberg, was about 50 km north of Tolagnaro (Fort Dauphin ) found natural hybrids between E.milii and E. lophogona represent another group that is known as the ' Heidelberger hybrids '. Rauh she described formally as Euphorbia x lomi, the first syllable of each of them parents' name ( lophogona, milii ) gave the new name. Compared to the California hybrids have the Heidelberger hybrids thinner stems and smaller but thicker leaves.

Form a third group originating from Thailand hybrids. Their origin is unknown, but is because of their very large cyathophylls the conjecture suggests that a parent E. milii var is tananarivae. In Thailand and other Asian countries, known as ' Poysean hybrids ' varieties are regarded as good luck charms, which led to much zeal breeding sector and a wide distribution of plants.

All of these hybrids are ideal houseplants and like a bright, semi- shady spot on the windowsill. As the natural way they need in winter at least 12 to 15 °, with adequate irrigation but have no problems with it, to stand next to radiators. They tolerate and like it, to be cast in the winter retain their leaves for several years and bloom almost all year round. Mildew occurs less frequently than in the natural way, but can occur in high humidity.

Since all species of section Goniostema are crossable with each other, find themselves in the trade now also hybrids of E. milii with another parent as E. lophogona. A native of Nathan Wong of the Honolulu Botanical Gardens hybrids E. milii × E. decaryi var spirosticha was first offered in 1999 in Grigsby 's Catalog (USA) and named in honor of the Creator E. ' Nat Wong '. Another cross Nathan Wong, E. milii × E. moratii, is characterized by its unusual marbled leaves and is called E. ' Hawaii '. Only recently in the trade is E. ' Honkeytonk ', a hybrid of E. milii × E. didiereoides with orange cyathophylls.

Toxicity

According to a study by the Research Center for Environment and Health, the substance diterpene esters contained in the sap of Euphorbia Euphorbia lomi and leuconeura should be able to act as a tumor promoter through the activation of cancer cells in conjunction with any other carcinogenic substance. Therefore, one should when handling these plants ensure that no milk juice gelange on the skin.

Gallery

Varieties

Euphorbia milii var longifolia

Euphorbia milii var a Flowering shrub splendens

Euphorbia milii var inflorescence of a Vulcanii

Hybrids

E. ' Siraya ': The cyathophylls are pale in winter

E. ' Siraya ': Explore open buds

E. ' Siraya ': the Cyathophyllenpaar reached a diameter of 6 cm.

Thorny branches

Inflorescence

Pink color end cyathophylls

Almost White cyathophylls

Red cyathophylls

Yellow cyathophylls

E. ' Nat Wong '

E. ' Hawaii '

E. ' Honkeytonk '

Cyathium Léon Croizat Bojort

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