Hayweeds
Hayweeds | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Ludwigia sedoides |
||||||||||||
Systematics | ||||||||||||
|
||||||||||||
Scientific name of the subfamily | ||||||||||||
Ludwigioideae | ||||||||||||
WLWagner & Hoch | ||||||||||||
Scientific name of the genus | ||||||||||||
Ludwigia | ||||||||||||
L. |
The hay herbs or Ludwigia ( Ludwigia ) is the only plant genus of the subfamily of the Ludwigioideae within the family of the evening primrose family (Onagraceae) with around 80 species.
description
Habitus
Hay herbs are upright to prostrate, slender, annual or perennial herbaceous plants , occasionally shrubs or rarely small trees . Some species grow floating in open water. In species that grow in water, the submerged parts of the plants are usually swollen and spongy or form white, sponge-like pneumatophores . The foliage is alternate or opposite , rarely arranged in a whorl . Stipules are reduced, but fall off early.
Inflorescences and flowers
Occasionally there are two bracts at the base of the ovary . The flowers are either individually in the upper leaf axils or in spike-like or racemose inflorescences. The flowers are radial symmetry . A hypanthium is missing. The three to seven, usually four to five, green sepals remain in place during the fruiting period. The number of yellow or occasionally white petals that fall off early from flowering corresponds to that of the sepals, but they can also be absent. The number of stamens is either equal to or twice that of the sepals. The anthers are either freely movable or attached to the base, the pollen is released as a monad , tetrad or polyad. The ovary is subordinate. The scar is either simple or lobed.
Fruits and seeds
Inverted egg-shaped to cylindrical capsule fruits are formed. They either open through a dehiscence or release the numerous small, rounded or slightly elongated seeds through a pore on the capsule.
Known chromosome numbers are 2n = 16, 32, 48, 64, 80, 96 and 128.
Occurrence
The genus can be found worldwide on all continents (with the exception of Antarctica), its main distribution is in the tropical zones of the Paleotropic , but also extends to temperate areas and the Neotropic .
The Ludwigia species colonize wet, open locations; occasionally they are also pure water plants and are used as such in aquaristics as aquarium plants ( e.g. Ludwigia ovalis, native to China, Japan, Taiwan and Thailand, or Ludwigia inclinata var. From Cuba and Venezuela . verticillata. ), the best growing species in the aquarium being the bastards Ludwigia repens x L. arcuata and Ludwigia arcuata x L. repens .
![](https://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/Ludwigia_July_2011-1.jpg/220px-Ludwigia_July_2011-1.jpg)
![](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Ludwigia_palustris_lupa_001_pvp.jpg/220px-Ludwigia_palustris_lupa_001_pvp.jpg)
Systematics
Ludwigia is the only genus in the subfamily of the Ludwigioideae. The hayweeds differ significantly from all other genera in the family. This and the results of anatomical and molecular genetic studies show that they represent a sister group to all other representatives of the family. For a long time, species with twice the number of stamens were listed as a separate genus Jussiaea , but this was combined with the Ludwigia when it could be proven that this represents a variable characteristic without diagnostic value.
Naming
Carl von Linné named the genus in 1753 after the German doctor and botanist Christian Gottlieb Ludwig (1709–1773).
Types (selection)
There are about 80 species in the genus Ludwigia :
|
literature
- 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. (on-line)
- Walter Erhardt among others: The big pikeperch. Encyclopedia of Plant Names . Volume 2. Verlag Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5406-7 .
Individual evidence
- ↑ Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , pp. 344–355.
- ^ Hans-Georg Kramer: Plant aquaristics á la Kramer. Tetra-Verlag, Berlin-Velten 2009, ISBN 978-3-89745-190-2 , pp. 176-185.
- ↑ Christel Kasselmann (1999), p. 354.
- ↑ a b c d e f g h i j k l m n Ludwigia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- ↑ Christel Kasselmann (1999), p. 344.
- ↑ Christel Kasselmann (1999), p. 345.
- ↑ Christel Kasselmann (1999), p. 346 f.
- ^ Hans-Georg Kramer: Plant aquaristics á la Kramer. Tetra-Verlag, Berlin-Velten 2009, ISBN 978-3-89745-190-2 , p. 176 f. ( Ludwigia aff. Glandulosa , wine red Ludwigia ; Syn .: Ludwigia repens "Rubin").
- ↑ Christel Kasselmann (1999), p. 348.
- ↑ Christel Kasselmann (1999), p. 349 f.
- ↑ Christel Kasselmann (1999), pp. 352-354.