Polycnemeae

Polycnemeae
	Nitrophila occidentalis
Systematics
	Eudicotyledons
	Nuclear eudicotyledons
Order :	Clove-like (Caryophyllales)
Family :	Foxtail family (Amaranthaceae)
Subfamily :	Polycnemoideae
Tribe :	Polycnemeae
Scientific name of the subfamily
	Polycnemoideae
	Ulbr.
Scientific name of the tribe
	Polycnemeae
	( Dumort. ) Moq.

Polycnemeae is the only tribe of the subfamily Polycnemoideae within the foxtail family (Amaranthaceae). They used to be part of the goosefoot family (Chenopodiaceae).

features

They are mostly low-growing herbs, some species also become shrub-like due to weak lignification. In contrast to all other representatives of the foxtail family , the Polycnemoideae have a normal growth in thickness . The leaves are alternate or opposite on the stem, their shape is often linear or sub-like. It is characteristic that the stomata of the leaves are arranged parallel to the central rib.

Cartilage ( Polycnemum arvense ), illustration

The hermaphroditic, inconspicuous flowers stand individually in the axilla of a bract and two bracts. The inflorescence consists of dry-skinned, white or pink-colored tepals . The stamens of the one to five stamens are united at the base to form a short but clear tube (as in the species of the subfamily Amaranthoideae ). The genus Polycnemum has anthers with only one counter and two pollen sacs (like the species of the subfamily Gomphrenoideae ). The tepals remain largely unchanged during the fruiting season.

Photosynthetic pathway

All species of the Polycnemoideae are C ₃ plants , which is considered an original characteristic.

Nitrophila mohavensis in its natural habitat

Greater cartilage ( Polycnemum majus ), herbarium specimen

Spread and evolution

The Polycnemoideae occur in the temperate regions of Eurasia (Central and Southern Europe , northwestern Africa , Central Asia ), in America and in Australia .

The Polycnemoideae split from the Amaranthaceae s in the Eocene . st. from. On the border from the Eocene to the Oligocene , the subfamily divided into a lineage in the northern hemisphere , which was the ancestor of the genus Polycnemum , and a line predominantly occurring in the southern hemisphere with the ancestors of Nitrophila , Hemichroa and Surreya . It is believed that an Antarctic connection existed between these southern ancestors at that time. The genus Nitrophila developed in South America and later spread over long distances to North America . The genera diversified in the Miocene and Pliocene , the few and rare species today are considered relics.

Systematics

The systematic assignment of the Polycnemoideae has long been controversial. This taxon was set up in 1827 as a tribe Polycnemeae within the goosefoot family (Chenopodiaceae) by Barthélemy Charles Joseph Dumortier (In Florula Belgica ). This group was later assigned to the Amaranthaceae family, for example by Alfred Moquin-Tandon (1849 in Prodromus systematis naturalis regni vegetabilis , Volume 13). Oskar Eberhard Ulbrich raised the group to the rank of subfamily in 1934 and put it back to the goosefoot family (in Engler & Prantl: The natural plant families , Vol. 16c, pp. 379-584). The two families are now united in the Amaranthaceae. Phylogenetic research has shown that the Polycnemoideae represent one of the basal lines of development in the evolution of the Amaranthaceae family.

The subfamily Polycnemoideae contains only the tribe Polycnemeae. These include four genera with 13 species:

Hemichroa R.Br. : Characteristic are alternate, linear, fleshy leaves and papillary scars all around. With only one species in Australia :
- Hemichroa pentandra R.Br.
Nitrophila S. Watson : It is characterized by opposite leaves and papillary scars only on the inside. With four types in North America , Central America and South America :
- Nitrophila atacamensis (Phil.) Ulbr.
- Nitrophila australis Chodat & Wilczek
- Nitrophila mohavensis Munz & JC Roos : It occurs in California and Nevada.
- Nitrophila occidentalis (Moq.) S. Watson : It is found in California, Nevada, Utah and Oregon.
Cartilage herbs ( Polycnemum L. ): They have alternate, awl-like leaves that are not fleshy. Your scars are papillary all around. With six species in Eurasia (Central and Southern Europe, Northwest Africa, Central Asia ):
- Field cartilage ( Polycnemum arvense L. )
- Polycnemum fontanesii Durieu & Moq.
- Heuffels cartilage herb ( Polycnemum heuffelii Láng )
- Greater cartilage herb ( Polycnemum majus A.Braun ex Bogenh. )
- Polycnemum perenne Litv.
- Warty cartilage ( Polycnemum verrucosum Láng )
Surreya R. Masson & G. Kadereit , with two species in Australia:
- Surreya diandra (R. Br.) R. Masson & G. Kadereit ( Syn.Hemichroa diandra R. Br. )
- Surreya mesembryanthema (R. Br.) R. Masson & G. Kadereit ( Syn.Hemichroa mesembryanthema R. Br. )

literature

Gudrun Kadereit, Thomas Borsch, Kurt Weising & Helmut Freitag: Phylogeny of Amaranthaceae and Chenopodiaceae and the evolution of C ₄ photosynthesis . In: International Journal of Plant Sciences Volume 164 (6), 2003, pp. 959-986. (Characteristics, distribution, photosynthetic pathway, systematics)

Individual evidence

↑ ^a ^b ^c ^d Polycnemoideae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
↑ ^a ^b ^c ^d ^e ^f Rüdiger Masson & Gudrun Kadereit: Phylogeny of Polycnemoideae (Amaranthaceae): Implications for biogeography, character evolution and taxonomy . In: Taxon 62 (1), 2013, pp. 100–111. [1]

Web links

Commons : Polycnemoideae - collection of images, videos and audio files

[GRIN-1] Polycnemoideae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.

[Masson-2] ↑ ^a ^b ^c ^d ^e ^f Rüdiger Masson & Gudrun Kadereit: Phylogeny of Polycnemoideae (Amaranthaceae): Implications for biogeography, character evolution and taxonomy . In: Taxon 62 (1), 2013, pp. 100–111. [1]