Hayweeds

Hayweeds
Ludwigia sedoides
Systematics
Rosids Eurosiden II Order : Myrtle-like (Myrtales) Family : Evening primrose family (Onagraceae) Subfamily : Ludwigioideae Genre : Hayweeds
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.

Flower of Ludwigia peruviana

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 .

Large-flowered hayweed ( Ludwigia grandiflora )

Ludwigia octovalvis

Marsh hayweed ( Ludwigia palustris )

Ludwigia peploides

Ludwigia prostrata

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 :

Ludwigia adscendens (L.) H. Hara : The home is tropical Asia, China and Australia. Ludwigia alata Elliott Rattling hayweed ( Ludwigia alternifolia L. ), occurs in North, Central and South America Ludwigia arcuata Walter , the narrow-leaved Ludwigia, occurs in the eastern United States Ludwigia bonariensis (Micheli) H. Hara : The home is Alabama, Florida, North Carolina, Bolivia, Paraguay, Uruguay and Argentina. Ludwigia brevipes (Long) Eames : The short-stemmed Ludwigia is native to the southeast coast of the USA Ludwigia curtissii Chapm. Ludwigia decurrens Walter : The home is North, Central and South America. As a neophyte, the species also occurs in Asia, Africa and France. Ludwigia erecta (L.) H. Hara : The home is North, Central and South America. As a neophyte it also occurs in Africa and India. Ludwigia glandulosa Walter , common in North America Large-flowered hayweed ( Ludwigia grandiflora (Michx.) Greuter & Burdet ; Syn .: Ludwigia uruguayensis (Camb.) Hara ), occurs in the USA, is naturalized in Spain and France Ludwigia helminthorrhiza (Mart.) H. Hara , occurs in southern Mexico, Central and South America Ludwigia hexapetala (Hook. & Arn.) Zardini, H. Gu & PH Raven : The home is North, Central and South America. Ludwigia hirtella Raf. Ludwigia hyssopifolia (G. Don) Exell : Home is Africa and Cape Verde, China and tropical Asia, Australia, Micronesia as well as South and Central America. Ludwigia inclinata (L. f.) M. Gómez , native to Central and South America Ludwigia lanceolata Elliott Ludwigia leptocarpa (Nutt.) H. Hara Ludwigia linearis Walter Ludwigia linifolia Poir. : The home is the southeastern USA. Ludwigia longifolia (DC.) H. Hara : It is native to Brazil, Argentina, Paraguay and Uruguay. The species is also naturalized in Australia. Ludwigia maritima R.M. Harper Ludwigia microcarpa Michx. Swimming hayweed ( Ludwigia natans (L.) Elliott ) occurs in the United States, Mexico, and the West Indies Ludwigia octovalvis (Jacq.) PH Raven : The home is Africa, Asia, Australia, North, Central and South America as well as the islands in the Pacific. Marsh hayweed ( Ludwigia palustris (L.) Elliott ), occurs in Europe, Africa, the Middle East, North and Central America, and is also naturalized in New Zealand Ludwigia peploides (Kunth) PH Raven : The home is North, Central and South America as well as Australia and New Zealand. Peruvian hayweed ( Ludwigia peruviana (L.) H. Hara ) occurs in South and Central America and in Florida Ludwigia pilosa Walter Ludwigia polycarpa Short & Peter : The home is eastern Canada and the USA. Ludwigia ravenii C.I. Bang Ludwigia repens J.R. Forest. : The home is North and Central America and Colombia. Several varieties and crosses ofthe creeping Ludwigia are known. Ludwigia sedoides (Humb. & Bonpl.) H. Hara : The home of the Sedum -like Ludwigia is Mexico, Central and South America. Ludwigia simpsonii Chapm. Ludwigia spathulata Torr. & A. Gray Ludwigia sphaerocarpa Elliott Ludwigia suffruticosa (L.) M. Gómez , occurs in the tropics Ludwigia virgata Michx. : The home is the southeastern USA.

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

1. ↑ Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , pp. 344–355.
2. ^ Hans-Georg Kramer: Plant aquaristics á la Kramer. Tetra-Verlag, Berlin-Velten 2009, ISBN 978-3-89745-190-2 , pp. 176-185.
3. ↑ Christel Kasselmann (1999), p. 354.
4. ↑ ^{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.
5. ↑ Christel Kasselmann (1999), p. 344.
6. ↑ Christel Kasselmann (1999), p. 345.
7. ↑ Christel Kasselmann (1999), p. 346 f.
8. ^ 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").
9. ↑ Christel Kasselmann (1999), p. 348.
10. ↑ Christel Kasselmann (1999), p. 349 f.
11. ↑ Christel Kasselmann (1999), pp. 352-354.

Web links

Commons : Heusenkräuter ( Ludwigia )  - Collection of images, videos and audio files