Alligator herb

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Alligator herb
Alligator herb (Alternanthera philoxeroides)

Alligator herb ( Alternanthera philoxeroides )

Systematics
Nuclear eudicotyledons
Order : Clove-like (Caryophyllales)
Family : Foxtail family (Amaranthaceae)
Subfamily : Gomphrenoideae
Genre : Alternanthera
Type : Alligator herb
Scientific name
Alternanthera philoxeroides
( Mart. ) Griseb.

The alligator herb ( Alternanthera philoxeroides ) is a plant species in the foxtail family (Amaranthaceae). This aquatic and marsh plant is originally native to South America. It is considered an invasive plant in many areas of the world .

description

Appearance and leaf

The alligator herb grows as a perennial herbaceous plant . It thrives as a water and swamp plant in aquatic to semi-terrestrial areas and forms creeping stolons up to 5 meters long and often forms mats. The hollow stems are 55 to 120 cm long and branched. Young stems and the leaf axils are hairy white and older stems are bare.

The constantly against arranged on the stem leaves are pedunculated or sessile. If there is a petiole, it is 3 to 10 mm long and glabrous or slightly hairy. The herbaceous simple leaf blade is 2.5 to 7 cm long and 0.5 to 2 cm wide, more or less narrowly elliptical, obscured-lanceolate, oblong, oblong-obovate or ovate-lanceolate with a narrowed base as well as pointed or blunt upper end that is spiky. The spreading edge is smooth. The leaf surface is bare or ciliate and the upper side of the leaf is hairy with bristles.

Inflorescences and flowers

The alligator herb blooms in the warm season, for example in China from May to October. Usually laterally or rarely terminally above the inflorescence shafts, with a diameter of 0.8 to 1.7 cm, there are spherical inflorescences . The membranous and durable bracts and bracts are white and have a pointed upper end. The bracts are with a length of 2 to 2.5 mm less than half as long as the bracts and egg-shaped. The bracts are lanceolate with a length of about 2 mm.

The hermaphroditic flowers are radial symmetry . The five identical, white, shiny, membranous, bare bracts are lanceolate or oblong with a length of 5 to 6 mm with a pointed upper end. There are five stamens . The 2.5 to 3 mm long stamens are fused cup-shaped at their base. The oblong-linear or tongue-shaped Pseudo staminodien are about as long as the stamens. The Short-stalked ovary is egg-shaped and flattened.

Multiplication

Fruits and seeds were not observed on specimens outside the area of ​​origin; it is assumed that they - at least the neophytic stocks - reproduce exclusively vegetatively.

Chromosome number

The number of chromosomes is 2n = 100.

Occurrence

The wide, originally South American distribution area of Alternanthera philoxeroides includes French Guiana , Guyana , Suriname , Venezuela , Brazil , Bolivia , Peru , northern Argentina , Paraguay and Uruguay . The alligator herb has spread as a neophyte in many parts of the world and is considered an invasive plant in Australia , the People's Republic of China , Taiwan , New Zealand , Thailand , the Caribbean islands and the USA .

The alligator herb is grown in central China, Java , Kalimantan and Louisiana .

Taxonomy

This kind in 1825 under the name (Basionym) Bucholzia philoxeroides by Carl Frederick Philip of Martius in Novorum Actorum Academiae Caesareae Leopoldinae-Carolinae Naturae Curiosorum , Volume 13 (1), pp 107 first described . August Grisebach placed them in 1879 in the Treatises of the Royal Society of Sciences in Göttingen , Volume 24, p. 36 in the genus Alternanthera . Other synonyms for Alternanthera philoxeroides (Mart.) Griseb. are: Achyranthes philoxeroides (Mart.) Standl. , Alternanthera philoxeroides fo. angustifolia Suess. , Alternanthera philoxeroides var. Acutifolia (Mart.) Hicken , Alternanthera philoxeroides var. Lancifolia Chodat , Alternanthera philoxeroides var. Luxurians Suess. , Alternanthera philoxeroides var. Obtusifolia (Mart.) Hicken , Bucholzia philoxeroides var. Acutifolia Mart. , Bucholzia philoxeroides var. Obtusifolia Mart. , Telanthera philoxeroides (Mart.) Moq. , Telanthera philoxeroides var. Acutifolia (Mart.) Moq. , Telanthera philoxeroides var. Denticulata Seub. in C.Martius, Telanthera philoxeroides var. linearifolia Chodat , Telanthera philoxeroides var. obtusifolia (Mart.) Moq. , Telanthera philoxeroides var. Obtusifolia Moq. , Telanthera philoxeroides var. Phyllantha Seub. in C.Martius. The specific epithet philoxeroides is derived from the Greek words phil (o) , "xer" for dry and "oid" for "have the shape like", one possible interpretation is: this species "looks like a land plant".

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Individual evidence

  1. ↑ a b c d e f g h i j Steven E. Clemants: Alternanthera in der Flora of North America , Volume 4: Alternanthera philoxeroides , p. 454 - same text online as the printed work , In: Flora of North America Editorial Committee (ed .): Flora of North America North of Mexico , Volume 4 - Magnoliophyta: Caryophyllidae, part 1 , Oxford University Press, New York and Oxford, 2003, ISBN 0-19-517389-9 .
  2. ↑ a b c d e f g h i j Bojian Bao, Thomas Borsch & Steven E. Clemants: Amaranthaceae : Alternanthera philoxeroides , p. 426 - the same text online as the printed work , In: Wu Zhengyi, Peter H. Raven & Deyuan Hong ( Ed.): Flora of China , Volume 5 - Ulmaceae through Basellaceae , Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, December 19, 2003, ISBN 1-930723-27-X .
  3. ↑ a b c d Alternanthera philoxeroides in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  4. ↑ Invasive Species .
  5. ↑ Alternanthera philoxeroides at Tropicos.org. Missouri Botanical Garden, St. Louis
  6. ↑ data sheet at alabamaplants .

Web links

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