Prickly lettuce

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Prickly lettuce
Spiny lettuce (Lactuca serriola), illustration

Spiny lettuce ( Lactuca serriola ), illustration

Systematics
Euasterids II
Order : Astern-like (Asterales)
Family : Daisy family (Asteraceae)
Subfamily : Cichorioideae
Genre : Lettuce ( Lactuca )
Type : Prickly lettuce
Scientific name
Lactuca serriola
L.
Prickly lettuce
Inflorescence and fruit cluster with caterpillar of the compass lettuce owl

The prickly lettuce ( Lactuca serriola ) and Compass Cos or fence cos called, is a plant from the genus lettuce ( Lactuca ) within the family of Compositae (Asteraceae).

description

The prickly lettuce is an annual hibernating to biennial herbaceous plant that reaches heights of 30 to 120 cm. It can develop roots up to 2 m deep . The plant produces a white latex from which natural rubber can be obtained.

The plant has alternate leaves on the stem , which are often vertical with their leaf blades and often point north or south. It is therefore considered a compass plant . The leaves are deeply lobed (type form: forma serriola ) or lanceolate and unlapped (forma integrifolia ), the leaf margin is always more or less roughly serrated. The spines on the midrib are longer than their mutual distance.

There are many cup-shaped inflorescences on a plant . The flower heads contain only 12 to 20 ray florets . The overgrown petals are yellow and unevenly purple. The light gray-brown achenes are rough and about 2.5 to 3.5 mm long, with a white, (3 to) 4 to 5 mm long pappus .

It blooms from July to September.

The number of chromosomes is 2n = 18.

Distribution and locations

The area of ​​distribution of the lettuce extends in a south-north direction from Ethiopia and the Mediterranean area to the north into the temperate zone ; there the deposits are concentrated in low-lying areas and warm areas. The species is also widespread in Germany. In a west-east direction, the distribution area extends from the Atlantic Islands to Mongolia , Xinjiang in western China, Afghanistan and northern India. It was introduced to southern Africa, East Asia, Australia, New Zealand, North America and southern South America.

The spiny lettuce is often found in sunny, gappy weed meadows, on roadsides, rubble and rubble sites, in railways and loading facilities, on walls, dams and in hedges. It is a character species of the plant communities of Conyzo-Lactucetum serriolae or Lactuco-Sisymbretum altissimi from the Sisymbrion association, but also occurs in societies of the Dauco-Melilotion or Convolvulo-Agropyrion associations . It prefers dry, nutrient-rich soils in warm, sunny locations.

According to Ellenberg , it is a full-light plant, a heat pointer and an association character of annual ruderal societies in a moderately warm climate ( Sisymbrion ).

Systematics

Lactuca serriola was first published in 1756 by Carl von Linné in Centuria II. Plantarum . An important synonym published in 1763 (with the old Middle Latin plant name scariola as a specific epithet) is Lactuca scariola L.

The prickly lettuce is the stem of our garden salad ( Lactuca sativa ). Genetic studies show such great similarities between the cultivated form Lactuca sativa and the wild form Lactuca serriola that a split into two species does not seem justified.

The shape of the stem leaves of Lactuca serriola f. serriola and f. integrifolia (SF Gray) SD Prince & RN Carter is hereditary and not linked by transitions. Plants with both leaf shapes occur regionally, but sometimes also next to each other in the same place of growth.

ecology

This species has a pronounced adaptation to drought and solar radiation: Leaves in sunny places are in the "compass position": The blade is vertical, its narrow side is oriented in a north-south direction, parallel to the solar radiation. This means that the leaf blades are fully exposed to the less intense sunlight in the morning and afternoon. However, when the sun is at its highest point at noon, the edges of the leaves face the sun.

Since the lettuce has differences in leaf orientation depending on its location, there is likely to be a tropism here . Plants standing in the shade do not show such an orientation of the leaf blades, it can even happen on a slope that the shaded leaves are oriented horizontally, but the sunny leaves have a vertical north-south direction.

The reorientation of the leaf blade in compass plants comes about through a growth and torsional movement of the petiole. Therefore, the spread position is retained after the growth is complete.

The flowers are pollinated by insects , and self-pollination also takes place.

Predators and parasites

The lettuce is the food plant for the compass lettuce owl ( Hecatera dysodea ) and for the lettuce monk ( Cucullia lactucae ). While the caterpillars of the compass lettuce owl are rather inconspicuous green to light brown, the caterpillars of the lettuce monk show a striking white-yellow-black color.

The following fungi parasitize the lettuce, namely the powdery mildew species Golovinomyces cichoracearum , Bremia lactucae and Sphaerotheca fusca as well as the two rust fungi Puccinia opizii (with host change to sedges ) and Puccinia maculosa (without host change).

literature

  • 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 .
  • 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 .
  • 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 .
  • 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 .
  • Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany. A botanical-ecological excursion companion to the most important species . 6th, completely revised edition. Quelle & Meyer, Wiebelsheim 2005, ISBN 3-494-01397-7 .
  • Wolfgang Hensel: Plants in Action. Bending, flapping, skidding. Spektrum Akademischer Verlag, Heidelberg 1993, ISBN 3-86025-061-2 .
  • Friedemann Klenke, Markus Scholler: Small plant parasitic mushrooms. Springer Verlag, Berlin-Heidelberg 2015, ISBN 978-3-642-55330-1
  • John L. Strother: Lactuca. In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 19: Magnoliophyta: Asteridae, part 6: Asteraceae, part 1 (Mutisieae – Anthemideae). Oxford University Press, New York / Oxford a. a. 2006, ISBN 0-19-530563-9 , pp. 262 (English, online ). (engl.).

Individual evidence

  1. ↑ Prickly lettuce latest potential rubber plant at rubbernews, July 24, 2015, accessed on January 17, 2018.
  2. ↑ John L. Strother: Lactuca. In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 19: Magnoliophyta: Asteridae, part 6: Asteraceae, part 1 (Mutisieae – Anthemideae). Oxford University Press, New York / Oxford a. a. 2006, ISBN 0-19-530563-9 , pp. 262 (English, online ). (engl.).
  3. ↑ a b 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 , pp.  988-989 .
  4. ^ Gerhard Wagenitz (Ed.): Illustrated flora of Central Europe. Pteridophyta, Spermatophyta . Founded by Gustav Hegi. 2nd revised and expanded edition. Volume VI. Part 4: Angiospermae, Dicotyledones 4 (Compositae 2, Matricaria - Hieracium) . Paul Parey, Berlin / Hamburg 1987, ISBN 3-489-86020-9 , pp. 1110–1112 (revised reprint of the 1st edition (Volume VI / 2 from 1929) with addendum).
  5. ↑ a b Zhu Shi, Norbert Kilian: Lactuca. In: Wu Zheng-yi, Peter H. Raven, Deyuan Hong (Eds.): Flora of China . Volume 20-21: Asteraceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 2011, ISBN 978-1-935641-07-0 , pp. 237 (English, online ).
  6. ^ Carl von Linné: Centuria II. Plantarum. Upsala 1756, p. 29, digitizedhttp: //vorlage_digitalisat.test/1%3Dhttp%3A%2F%2Fbiodiversitylibrary.org%2Fpage%2F36017994~GB%3D~IA%3D~MDZ%3D%0A~SZ%3D~ double-sided%3D~LT%3D~ PUR% 3D .
  7. ↑ WJM Koopman, MJ Zevenbergen, RG Van den Berg: Species relationships in Lactuca sl (Lactuceae, Asteraceae) inferred from AFLP fingerprints. In: American Journal of Botany. Volume 88, No. 10, 2001, pp. 1881-1887, abstract and full text .
  8. ↑ SD Prince, RN Carter: Prickly Lettuce (Lactuca serriola L.) in Britain. In: Watsonia. Volume 11, No. 4, 1977, pp. 331-338 (PDF file) .
  9. ↑ Friedemann Klenke: Collection and identification aids for phytoparasitic small mushrooms in Saxony . In: Reports of the Working Group of Saxon Botanists, New Series. Volume 16, 1998, Institute for Botany at the University of Dresden.

Web links

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