Halothamnus

Halothamnus subaphyllus ssp. charifii

Halothamnus is a genus of flowering plants in the family Amaranthaceae ( Amaranthaceae ). The botanical genus name Halothamnus derives from the Greek words ἅλς ( neck ) for salt and θαμνος ( thamnos ) for shrub from and thus means " salt bush "; which may refer both to the often salty growth places as well as on the salt accumulation in the plants.

Description

Most Halothamnus species are small shrubs and subshrubs, two types are Annuals. The leaves alternate sitting and without basal taper at the stem. They are simple, entire, in cross section, almost cylindrical, concave or flat and slightly fleshy ( succulent ).

The hermaphrodite flowers are inconspicuous and sit individually in the armpit of a supporting sheet ( bract ) and two lateral bracteoles ( Brakteolen ). Her five adult non bloom ( tepals ) are in the lower part colorless, above a cross furrow greenish with membranous margin. Envelop five stamens which spring flowers on the basis of a shell-like structure ( hypogyner discus ). Two carpels are fused into a superior ovaries. The stylus is widened to the base and bears at the top two scars.

The single-seeded, horizontally flattened fruit should abide by the hardening perianth ( perianth ) enclosed. From the cross- furrow on the back of the tepals grow from membranous, striped wings. Thicken beneath the wings and the tepals become woody and form a tube with flat base, but without fused together. On the underside of the fallen fruit of five pits are annular to recognize which are surrounded by a wall. This fruit features are characteristic of the genus Halothamnus.

Bottom of a fruit of Halothamnus iranicus.

The pollen grains are almost spherical, 18 to 38 microns in diameter, and have the whole surface is distributed about 12 to 29 pores ( pantoporat ), as is typical of the goosefoot. The individual species differ in pollen size and number of pores, the more southern species, the smallest and the northern species have the largest pollen grains.

Pollination and fruit spread

For all types of Halothamnus first bloom on the dust bag, only after their pollination is the scars ( Proterandrie ) unfold. In Halothamnus subaphyllus pollination was detected by insects ( entomophily ). Of the other species, there are no observations, but there is much to suggest that they are also insektenblütig.

The area enclosed by the hardening perianth fruits are spread by the wind ( Anemochorie ), the 20 mm diameter discs large wing for buoyancy care.

Photosynthetic

All Halothamnus species possess an anatomical leaf structure with wreath Anatomy of Salsola type. Physiological investigations confirmed that photosynthesis proceeds via the C4 pathway ( C4 plants ).

Occurrence

The distribution of the genus Halothamnus ranges in north-south direction from Kazakhstan to Somalia, and in west-east direction from the Sinai Peninsula to the Dshungarei in China. Particularly rich in species are the highlands of Iran and Afghanistan and Central Asia (Uzbekistan, Turkmenistan ).

All Halothamnus species grow on dry sites of the semi-deserts and deserts, from the plains to altitudes of about 2800 meters in the mountains. They colonize stony, loamy or sandy soil, many Halothamnus species also tolerate salt or gypsum based surface.

Use

Some Halothamnus species are important forage for camels, sheep and goats, so they are cultivated for the reclamation of pastures, for example Halothamnus subaphyllus, Halothamnus auriculus and Halothamnus glaucus. Halothamnus subaphyllus also serves for the attachment of sandy areas and for the production of the alkaloid used medically salsoline. Halothamnus somalensis is used as a medicinal plant against parasitic worms. Before the introduction of potash mining alkalis were obtained for the soap factory from Halothamnus subaphyllus and Halothamnus glaucus.

System

The genus Halothamnus 1845 Hippolyte François Jaubert established by and Édouard Spach in Illustrationes Plantarum Orientalium, 2, 50, Table 136. As Lectotypusart 1874 Halothamnus bottae Jaub & Spach has been set. Synonyms for Halothamnus Jaub & Spach are Aellenia ( Ulbr. ) emend. Aellen and Salsola L. sect. Sphragidanthus Ilyin.

The genus Halothamnus is close to the genus salt herb ( Salsola ) and belongs to the subtribe Sodinae from the tribe Salsoleae in the subfamily within the family Amaranthaceae Salsoloideae. Phylogenetic studies have shown that the genus is monophyletic.

The genus is divided Halothamnus of Kothe -Heinrich in two sections and contains 21 species:

• Section Pungentifolia Kothe - Heinr. With the only kind: Halothamnus beckettii Botsch.

• Section Halothamnus: With approximately 20 types: Halothamnus afghanicus Kothe - Heinr.
• Halothamnus auriculus ( Moq. ) Botsch. 2 with two subspecies.
• Halothamnus bamianicus ( Gilli ) Botsch.
• Halothamnus bottae Jaub. & Spach: With two subspecies.
• Halothamnus cinerascens ( Moq. ) Kothe - Heinr. With two subspecies.
• Halothamnus ferganensis Botsch.
• Halothamnus glaucus ( M.Bieb. ) Botsch. With three subspecies.
• Halothamnus hierochunticus ( Bornm. ) Botsch.
• Halothamnus iliensis ( Lipsky ) Botsch.
• Halothamnus iranicus Botsch.
• Halothamnus iraqensis Botsch.
• Halothamnus kermanensis Kothe - Heinr.
• Halothamnus lancifolius ( Boiss. ) Kothe - Heinr.
• Halothamnus oxianus Botsch.
• Halothamnus schurobi ( Botsch. )
• Halothamnus seravschanicus Botsch.
• Halothamnus sistanicus ( De Marco & Dinelli ) Kothe - Heinr.
• Halothamnus somalensis ( N.E.Br. ) Botsch.
• Halothamnus subaphyllus ( C.Meyer ) Botsch. With three subspecies.
• Halothamnus turcomanicus Botsch.