Polycnemoideae
Nitrophila occidentalis
Polycnemeae is the only tribe of the subfamily Polycnemoideae within the family of Amaranthaceae ( Amaranthaceae ). Previously they were made the goosefoot family ( Chenopodiaceae ).
- 4.1 Notes and references
Features
There are mostly low herbs, some species are weak lignification also shrubby. In contrast to all other members of the Amaranthaceae the Polycnemoideae have a normal thickness growth. The leaves are alternate or opposite on the stem, their shape is often linear or subulate. It is characteristic that the stomata of the leaves are arranged parallel to the midrib.
The hermaphrodite, inconspicuous flowers appear singly in the axil of a supporting sheet and two bracteoles. The perianth consists of trockenhäutigen, white or pink tepals. The stamens of one to five stamens are united at the base into a short but clear tube (as in the species of the subfamily Amaranthoideae ). The genus has Polycnemum dust bag with only one bar and two pollen sacs (such as the species of the family Gomphrenoideae ). The tepals remain largely unchanged to fruit time.
Photosynthetic
All types of Polycnemoideae are C3 - plants, which is regarded as an original feature.
Dissemination 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 were split s.str in the Eocene of the Amaranthaceae. from. The subfamily informed on the border of the Eocene to Oligocene in a line of descent on the northern hemisphere, which was the ancestor of the genus Polycnemum, and a mostly occurring in the southern hemisphere line with the ancestors of Nitrophila, Hemichroa and Surreya. It is believed that at that time there was a connection between these Antarctic southern ancestors. The genus Nitrophila developed in South America and later spread over long distances up to North America. The genera diversified in the Miocene and Pliocene, the few and rare modern species are considered relics.
System
The systematic allocation of the Polycnemoideae has long been controversial. This taxon was erected in 1827 as a tribe Polycnemeae within the goosefoot ( Chenopodiaceae ) by Barthélemy Charles Joseph Dumortier ( In Florula Belgica ). Later this group was attributed to the foxtail plants (Amaranthaceae ), for example by Alfred Moquin - Tandon ( 1849 in Prodromus systematis naturalis regni vegetabilis, Volume 13). Oskar Eberhard Ulbrich got the group in 1934 in the rank of a subfamily, and set them to the Gänsefußgewächsen ( Engler & Prantl in: The natural plant families, Vol 16c, pp. 379-584 ). Meanwhile, the two families are united in the Amaranthaceae. Phylogenetic studies have shown that the Polycnemoideae be one of the basal lineages in the evolution of the Amaranthaceae family.
The subfamily contains only the Polycnemoideae Tribus Polycnemeae. These include four genera with 13 species:
- Hemichroa R.Br.: It is characterized by constant change, linealische, fleshy leaves and around papillary scarring. With only one kind in Australia: Hemichroa pentandra R.Br.
- Nitrophila atacamensis ( Phil.) Ulbr.
- Nitrophila australis Chodat & Wilczek
- Nitrophila Mohavensis Munz & J. C. Roos
- Nitrophila occidentalis ( Moq. ) S. Watson
- Arable coral necklace ( Polycnemum arvense L.)
- Polycnemum fontanesii Durieu & Moq.
- Heuffels coral necklace ( Polycnemum heuffelii Láng )
- Large coral necklace ( Polycnemum majus A.Braun ex Bogenh. )
- Polycnemum perenne Litv.
- Warty coral necklace ( Polycnemum verrucosum Láng )
- 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 )