| Polycnemoideae | |
|---|---|
 | |
| Nitrophila occidentalis | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Amaranthaceae |
| Subfamily: | Polycnemoideae Ulbr. |
| Genera | |
4 genera, see text | |
The Polycnemoideae are a small subfamily of plants in the family Amaranthaceae, representing a basal evolutionary lineage. The few relictual species are distributed in Eurasia and North Africa, North America, and Australia.
The subfamily Polycnemoideae comprises small herbs; some species are weakly lignified and grow shrublike. The subfamily is distinguishable from all other members of Amaranthaceae by normal secondary growth. The alternate or opposite leaves are often linear or subulate. The stomata of the leaves are arranged in parallel to the midveins. [1]
The bisexual flowers are sitting solitary in the axil of a bract and two bracteoles. The inconspicuous perianth is formed of chartaceous, scarious, white or pinkish tepals. One to five stamens are present with their filaments united in a short but distinct filament tube (like in subfamily Amaranthoideae). Anthers are with only one lobe and two pollen sacs (bilocular, like in subfamily Gomphrenoideae). In fruit, the tepals are never conspicuously modified. [1]
The Polycnemoideae are all C3-plants. This is considered a primary character. [1]
The Polycnemoideae are distributed in the temperate regions of Eurasia (central and southern Europe, northwestern Africa, Central Asia), North America, and Australia. [1]
Polycnemoideae began to diverge from Amaranthaceae s.str. in Eocene. At the edge from Eocene to Oligocene, the subfamily split into a lineage on the Northern Hemisphere, which was the ancestor of Polycnemum , and a lineage predominantly occurring on the Southern Hemisphere with the ancestors of Nitrophila , Hemichroa , and Surreya . An antarctic connection of these southern ancestors is assumed. The genus Nitrophila developed in South America and dispersed later to North America. The genera of the subfamily diversified during Miocene and Pliocene, with only a few rare species that seem to be relictual. [2]
The intrafamilial position of the Polycnemoideae has long been a matter of dispute. The taxon was recognized in 1827 as Tribus Polycnemeae within the family Chenopodiaceae by Dumortier (In Florula Belgica). Later, it was treated as belonging to the family Amaranthaceae in 1849 by Moquin-Tandon (in Prodromus systematis naturalis.... Vol 13). Oskar Eberhard Ulbrich raised it to subfamilial level in 1934, again within Chenopodiaceae (in Engler & Prantl: Die natürlichen Pflanzenfamilien. Vol 16c). Today, both families are included in Amaranthaceae s.l. [1]
Phylogenetic research has revealed the Polycnemoideae represent a basal lineage of evolution within the family Amaranthaceae. [1]
The Polycnemoideae comprise only one tribe, Tribus Polycnemeae, [3] with four genera and 13 species: [2]
Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus Amaranthus. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it the most species-rich lineage within its parent order, Caryophyllales.
The Salicornioideae are a subfamily of the flowering plant family Amaranthaceae. Important characters are succulent, often articulated stems, strongly reduced leaves, and flowers aggregated in thick, dense spike-shaped thyrses. These halophytic plants are distributed worldwide.
The Salsoloideae are a subfamily of the Amaranthaceae, formerly in family Chenopodiaceae.
The Chenopodioideae are a subfamily of the flowering plant family Amaranthaceae in the APG III system, which is largely based on molecular phylogeny, but were included - together with other subfamilies - in family Chenopodiaceae in the Cronquist system. Food species comprise Spinach, Good King Henry, several Chenopodium species, Orache, and Epazote.
Atriplex is a plant genus of 250–300 species, known by the common names of saltbush and orache. It belongs to the subfamily Chenopodioideae of the family Amaranthaceae s.l.. The genus is quite variable and widely distributed. It includes many desert and seashore plants and halophytes, as well as plants of moist environments. The generic name originated in Latin and was applied by Pliny the Elder to the edible oraches. The name saltbush derives from the fact that the plants retain salt in their leaves; they are able to grow in areas affected by soil salination.
Beta is a genus in the flowering plant family Amaranthaceae. The best known member is the common beet, Beta vulgaris, but several other species are recognised. Almost all have common names containing the word "beet". Wild Beta species can be found throughout the Atlantic coast of Europe, the Mediterranean coastline, the Near East, and parts of Asia including India.
Halothamnus is a genus in the subfamily Salsoloideae of the family Amaranthaceae. The scientific name means saltbush, from the Greek ἅλς (hals) "salt" and θαμνος (thamnos) "bush". This refers either to salty habitats or to the accumulation of salt in the plants. The genus is distributed from Southwest and Central Asia to the Arabian peninsula and East Africa.
The Betoideae are a small subfamily of the flowering plant amaranth family, Amaranthaceae sensu lato. Commonly known members include beet, sugar beet, chard, and mangelwurzel, which all are cultivars of Beta vulgaris.
Camphorosmeae is a species-rich tribe of the Amaranthaceae, formerly Chenopodiaceae, with 20 genera and about 179 species. It is classified as a single tribe of subfamily Camphorosmoideae.
The Suaedoideae are a subfamily of plants in the family Amaranthaceae.
The Corispermoideae are a subfamily of the Amaranthaceae, formerly in family Chenopodiaceae.
Dysphania is a plant genus in the family Amaranthaceae, distributed worldwide from the tropics and subtropics to warm-temperate regions.
Halostachys is a genus of flowering plants in the plant family Amaranthaceae, containing a single species, Halostachys belangeriana. The plants are small to medium halophytic shrubs with apparently jointed fleshy stems and scale-like leaves. They are native to Asia and southeastern Europe.
Kalidium is a genus of flowering plants in the plant family Amaranthaceae. The species are shrubby halophytes distributed in Southeast Europe, Southwest Asia and Central Asia to China.
Chenopodiastrum is a genus of herbaceous flowering plants in the family Amaranthaceae. The genus was formally described in 2012. The 5 species occur in Eurasia, North Africa, and North America.
Heterostachys is a genus of flowering plants in the plant family Amaranthaceae. The two species are shrubby halophytes native to South America and Central America.
Allenrolfea is a genus of shrubs in the family Amaranthaceae. The genus was named for the English botanist Robert Allen Rolfe. There are three species, ranging from North America to South America.
Microcnemum is a genus in the plant family Amaranthaceae, containing a single species, Microcnemum coralloides. It is a dwarf annual halophyte with fleshy, apparently jointed stems and reduced leaves and flowers. The two subspecies show a disjunct distribution in Spain and Western Asia.
Acroglochin is a genus of flowering plants in the plant family Amaranthaceae, containing a single species, Acroglochin persicarioides. It is distributed from the Himalayas to China. The systematic position in subfamily Betoideae is still uncertain.
Patellifolia is a genus of flowering plants in the subfamily Betoideae of the plant family Amaranthaceae. These are mostly procumbent herbs occurring in the Western Mediterranean region and Macaronesia, with some isolated occurrences in North Africa and at the Horn of Africa. They are interesting as crop wild relatives of sugar beet.
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