Ludwigia (plant)

Ludwigia octovalvis

The Heusenkräuter ( Ludwigia ) is the only plant genus of the subfamily of Ludwigioideae within the family Onagraceae ( Onagraceae ) with about 80 species.

  • 3.1 naming
  • 3.2 Kinds (selection)

Description

Habit

Heusenkräuter are upright -growing to prostrate, slender, annual or perennial herbaceous plants, occasionally shrubs or rarely small trees. Some species grow -floating in open water. When growing in water species, the submerged parts of the plant are usually swollen and spongy or form white, sponge-like pneumatophores. The foliage is alternate or opposite, rarely whorled arranged. Stipules are reduced available, but fall off early.

Inflorescences and flowers

Occasionally, two bracts at the base of the ovary. The flowers are either single together in the upper leaf axils or in aged men or racemose inflorescences. The flowers are radial symmetry. A Hypanthium missing. The three to seven, usually four to five green sepals remain stand still during fruiting time. The number of yellow or occasionally white, early falling of the flower petals is consistent with the sepals, but they can also missing. The number of stamens is either equal to the sepals or is twice. The anthers are either freely or attached at the base, the pollen is released as a monad, tetrad or polyad. The ovary is inferior. The scar is either simple or lobed.

Fruit and seeds

There are inverted ovoid formed by cylindrical capsule fruits. They open either by a dehiscence or give numerous small, rounded or slightly elongated seeds through a pore on the capsule -free.

Known chromosome numbers 2n = 16, 32, 48, 64, 80, 96 and 128

Occurrence

The genus is worldwide in all continents ( except Antarctica ) to find their main application area lies in the tropical zones of the Paläotropis but ranges in temperate temperate areas and the Neotropics.

The Ludwigia species inhabit wet, open places, sometimes they are also pure water plants.

System

Ludwigia is the only genus in the subfamily of Ludwigioideae. The Heusenkräuter differ significantly from all other genera of the family. This and the results show anatomical and molecular genetic studies have shown that they are a sister group to all other members of the family. Lange species were performed with twice the number of stamens as a separate genus Jussiaea, but this was combined with the Ludwigia than could be shown that this is a variable feature without diagnostic value.

Naming

Carl Linnaeus named the genus in 1753 after a German physician and botanist Christian Gottlieb Ludwig ( 1709-1773 ).

Types (selection)

In the genus Ludwigia, there are about 80 species:

  • Ludwigia adscendens (L.) H. Hara
  • Ludwigia alata Elliott
  • Rattling Heusenkraut ( Ludwigia alternifolia L.), is found in North, Central and South America
  • Ludwigia arcuata Walter, occurs in the U.S.
  • Ludwigia bonariensis ( Micheli ) H. Hara
  • Ludwigia brevipes ( Long) Eames
  • Ludwigia curtissii Chapm.
  • Ludwigia decurrens Walter
  • Ludwigia erecta (L.) H. Hara
  • Ludwigia glandulosa Walter
  • Ludwigia grandiflora ( Michx. ) Greuter & Burdet ( Syn: Ludwigia uruguayensis ( Camb. ) Hara ), occurs in the U.S., is naturalized in Spain and France
  • Ludwigia helminthorrhiza ( Mart. ) H. Hara, occurs in Mexico, Central and South America
  • Ludwigia hexapetala ( Hook. & Arn. ) Zardini, H. Gu & PH Raven
  • Ludwigia hyssopifolia (G. Don ) Exell
  • Ludwigia inclinata ( L. f ) M. Gómez
  • Ludwigia lanceolata Elliott
  • Ludwigia leptocarpa ( Nutt. ) H. Hara
  • Ludwigia linearis Walter
  • Ludwigia linifolia Poir.
  • Ludwigia longifolia ( DC.) H. Hara
  • Ludwigia maritima R. M. Harper
  • Ludwigia microcarpa Michx.
  • Swimming Heusenkraut ( Ludwigia natans (L.) Elliott ), is found in the United States, Mexico and the West Indies
  • Ludwigia octovalvis ( Jacq. ) P.H. Raven
  • Marsh Heusenkraut ( Ludwigia palustris (L.) Elliott ), is found in Europe, Africa, Middle East, North and Central America, naturalized in New Zealand
  • Ludwigia peploides ( Kunth ) P.H. Raven
  • Peruvian Heusenkraut ( Ludwigia peruviana (L.) H. Hara ), is found in South and Central America as well as in Florida
  • Ludwigia pilosa Walter
  • Ludwigia polycarpa Short & Peter
  • Ludwigia ravenii C. I. Peng
  • Ludwigia repens J. R. Forst.
  • Ludwigia sedioides ( Humb. & Bonpl. ) H. Hara
  • Ludwigia simpsonii Chapm.
  • Ludwigia spathulata Torr. & A. Gray
  • Ludwigia sphaerocarpa Elliott
  • Ludwigia suffruticosa (L.) M. Gómez, is found in the tropics
  • Ludwigia virgata Michx.

Evidence

  • Peter C. Hoch, Peter H. Raven: Ludwigia, in: Flora of Pakistan, Vol 139, p 35, online
  • Jiarui Chen, Peter C. Hoch & Peter H. Raven: Ludwigia, in: Flora of China, Vol 13, pp. 400-401, online
  • Peter H. Raven, Ching -I Peng: Ludwigia, in: Digital Flora of Taiwan, online
  • Walter Erhardt et al: The big walleye. Encyclopedia of plant names. Volume 2 Eugen Ulmer Verlag, Stuttgart, 2008. ISBN 978-3-8001-5406-7
Ovary (botany) Stigma (botany) Wound dehiscence
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