Midsummer milkweed
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Midsummer milkweed |
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| Euphorbia helioscopia | ||||||||||||
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The midsummer milkweed ( Euphorbia helioscopia ) is a species of plant in the genus Wolfsmilch ( Euphorbia ) within the family of the milkweed family (Euphorbiaceae). The botanical and the German name indicate the peculiarity of the species to align its inflorescences to the sun ( heliotropism ).
description
The midsummer milkweed is an annual herbaceous plant that reaches heights of up to 40 centimeters, but most plants are only 10 to 20 cm high and remain unbranched or branch only slightly from the base. The cylindrical, up to 3 mm thick stem has only a few obovate leaves that are up to 2 cm long. The longitudinal growth is completed with a whorl of five leaves, above which the terminal inflorescence appears.
The inflorescence forms the largest part of the plant. It is a five-pointed umbel that is divided into three parts (trichotom). The bracts , which make up most of the foliage, are leaf-shaped, often slightly toothed and yellowish-green. The cyathia , which are only about 1 mm in size, are also yellowish-green . The cyathia formed first usually have five, the cyathia appearing on more branched inflorescence stalks usually only four broadly ovoid to almost circular nectar glands. The deeply lobed, three-chambered capsule fruit has a diameter of about 3 mm and protrudes from the cyathium on a curved stalk.
The entire vegetation period is roughly between March and November, the flowering period between April and October. At the end of the growing season, the plants are often attacked by powdery mildew . They die with the first frost at the latest .
The species has chromosome number 2n = 42.
ingredients
Like all milkweed species, this plant is also very poisonous.
ecology
The solstice milkweed is mostly a therophyte .
The flowers bloom by a civilization effect now even in winter. The inflorescences show a photonasty, that is, they face the sun. The pollination takes place mainly through flies . The main flowering time is from April to October.
The three-part split fruits disintegrate into 3 "cocci", which open explosively through a shock mechanism and throw the seeds, which are pitted in a net, up to 2 m away. The seeds are long-lived. Fruit ripening is from July to October. There is also apomixis , that is, the formation of seeds without fertilization .
Vegetative propagation is possible through root shoots. The species has roots up to 80 centimeters deep.
Occurrence
This species probably originates from the Mediterranean area and spread in the Neolithic as a cultural follower of humans ( archaeophyte ). The natural range of the species extends from North Africa over the whole of Europe and in Asia over Iran and India to China and Japan . In North and South America , introduced plants are feral ( invasive plant ).
The solstice milkweed is widespread in gutted weed meadows in chopped fields or in gardens and vineyards. It prefers loose soils rich in nitrogen and bases and shows clay and nutrient richness. According to Ellenberg , it is a freshness pointer, a weak acid to weak base pointer, growing in nitrogen-rich locations and an association character of the Erdrauch-Wolfsmilch societies (Fumario-Euphorbion).
The species rises in the Allgäu Alps in the Tyrolean part near Benglerwald between Holzgau and Bach up to 1200 m above sea level.
Systematics and taxonomy
Euphorbia helioscopia was first published in 1753 by Carl von Linné in Species Plantarum .
One can distinguish between two subspecies:
- Euphorbia helioscopia subsp. helioscopia : It occurs in Macaronesia, North Africa and from Eurasia to the Indian subcontinent.
- Euphorbia helioscopia subsp. hiemalis A.P. Khokhr. : It occurs in the Caucasus region.
gallery
Young plant
Typical plant: unbranched or slightly branched from the base, few leaves, five-leaved whorl, relatively large, yellow-green inflorescence
Typical branching pattern of the inflorescence
Midsummer milkweed pollen (400 ×)
swell
literature
- Siegmund Seybold (Ed.): Schmeil-Fitschen. Interactive flora of Germany. Seeing - determining - knowing. The key to the flora . CD-ROM, version 2.0. Quelle & Meyer, Wiebelsheim 2004, ISBN 3-494-01368-3 .
- Oskar Sebald, Siegmund Seybold, Georg Philippi (Hrsg.): The fern and flowering plants of Baden-Württemberg . tape 4 : Special part (Spermatophyta, subclass Rosidae): Haloragaceae to Apiaceae . Eugen Ulmer, Stuttgart (Hohenheim) 1992, ISBN 3-8001-3315-6 .
- Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany and neighboring countries. The most common Central European species in portrait. 7th, corrected and enlarged edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01424-1 .
Individual evidence
- ↑ a b c Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 .
- ↑ Margot Spohn, Marianne Golte-Bechtle: What is blooming there? The encyclopedia: over 1000 flowering plants from Central Europe. Kosmos, Stuttgart 2005, ISBN 3-440-10326-9 .
- ↑ Heinz Ellenberg : Vegetation of Central Europe with the Alps in an ecological, dynamic and historical perspective (= UTB for science. Large series . Volume 8104 ). 5th, heavily changed and improved edition. Eugen Ulmer, Stuttgart (Hohenheim) 1996, ISBN 3-8252-8104-3 .
- ↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 2, IHW, Eching 2004, ISBN 3-930167-61-1 , p. 193.
- ↑ Carl von Linné: Species Plantarum. Volume 1, Impensis Laurentii Salvii, Holmiae 1753, p. 459, digitized
- ↑ a b Rafaël Govaerts (Ed.): Euphorbia helioscopia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 20, 2020.
Web links
- Midsummer milkweed. In: FloraWeb.de.
- Profile and distribution map for Bavaria . In: Botanical Information Hub of Bavaria .
- Euphorbia helioscopia L. In: Info Flora , the national data and information center for Swiss flora . Retrieved December 2, 2015.
- Distribution in the northern hemisphere according to Eric Hultén
- Thomas Meyer: Data sheet with identification key and photos at Flora-de: Flora von Deutschland (old name of the website: Flowers in Swabia )
- The solstice milkweed as a poisonous plant
- Profile of the species ( Memento from January 16, 2005 in the Internet Archive )
