Sunday, 19 June 2016

Atriplex

Atriplex, is a plant genus of 250–300 species, known by the common names of
saltbush and orache (or orach). It belongs to the subfamily Chenopodioideae of the family Amaranthaceae (which include the Chenopodiaceae of the Cronquist system). 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.

The genus Atriplex is distributed nearly worldwide from subtropical to temperate and to subarctic regions. Most species rich are Australia, North America, South America and Eurasia. Many species are halophytes and are adapted to dry environments with salty soils.

The genus evolved in Middle Miocene, the C4-photosynthesis pathway developed about 14.1-10.9 million years ago, when the climate became increasingly dry. The genus diversified rapidly and spread over the continents. The C4Atriplex colonized North America probably from Eurasia during the Middle/Late Miocene, about 9.8-8.8 million years ago, and later spread to South America. Australia was colonized twice by two C4 lineages, one from Eurasia or America about 9.8-7.8 million years ago, and one from Central Asia about 6.3-4.8 million years ago. The last lineage diversified rapidly, and became the ancestor of most Australian Atriplex species.

Atriplex species are used as food plants by the larvae of some Lepidoptera species; see the list of Lepidoptera which feed on Atriplex. For spiders such as Phidippus californicus and other arthropods, saltbush plants offer opportunities to hide and hunt in habitat that is otherwise often quite barren.

The favored species for human consumption is now usually Garden Orache (A. hortensis), but many species are edible and the use of Atriplex as food is known since at least the late Epipaleolithic (Mesolithic).

Common Orache (A. patula) is attested as an archaeophyte in northern Europe, and the Ertebølle culture is presumed to have used it as a food.[citation needed] It's seed has been found among apparent evidence of cereal preparation and cooking at Late Iron Age villages in Britain. In the biblical Book of Job, mallûaḥ (מַלּ֣וּחַ, probably Mediterranean Saltbush, A. halimus, the major culinary saltbush in the region) is mentioned as food eaten by social outcasts (Job 30:4). Grey Saltbush (A. cinerea) is used as bushfood in Australia since prehistoric times. Chamiso (A. canescens) and Shadscale (A. confertifolia) were eaten by Native Americans, and Spearscale (A. hastata) was a food in rural Eurasia.

Meat from sheep which have grazed on saltbush has surprisingly high levels of vitamin E, is leaner and more hydrated than regular lamb and has consumer appeal equal to grain-fed lamb. The vitamin E levels could have animal health benefits while extending the shelf-life and maintaining the fresh red colour of saltbush lamb. This effect has been demonstrated for Old Man Saltbush (A. nummularia) and River Saltbush (A. amnicola). For reasons unknown, sheep seem to prefer the more fibrous, less nutritious River Saltbush.

Saltbushes are also used as an ornamental plant in landscaping and can be used to prevent soil erosion in coastal areas. Old Man Saltbush has also been successfully used to rehabilitate old mining sites around Lightning Ridge (Australia).

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