# Halothamnus

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{{Short description|Genus of flowering plants}}
{{Automatic taxobox
|image = Halothamnus_subaphyllus_ssp_charifii.JPG
|image_caption = [''Halothamnus subaphyllus'' subsp. ''charifii''](/source/Halothamnus_subaphyllus)
|display_parents = 2
|taxon = Halothamnus
|authority = [Jaub.](/source/Jaub.) & [Spach](/source/%C3%89douard_Spach)
|synonyms =
*''Aellenia'' <small>(Ulbr.) emend. Aellen (circumscription emended)</small>
*''Salsola'' <small>L.</small> sect. ''Sphragidanthus'' <small>Iljin</small>
|subdivision_ranks = Species
|subdivision = 21 species, see text
}}

'''''Halothamnus''''' is a genus in the subfamily [Salsoloideae](/source/Salsoloideae) of the family [Amaranthaceae](/source/Amaranthaceae) (s.l., now including Chenopodiaceae). The scientific name means "saltbush", from the [Greek](/source/Greek_language) {{lang|el|ἅλς}} ({{translit|el|hals}}) {{gloss|salt}} and {{lang|el|θαμνος}} ({{translit|el|thamnos}}) {{gloss|bush}}. This refers either to salty habitats or to the accumulation of salt in the plants. The genus is distributed from [Southwest](/source/Southwest_Asia) and [Central Asia](/source/Central_Asia) to the [Arabian Peninsula](/source/Arabian_Peninsula) and [East Africa](/source/East_Africa).

== Description ==
Most species of ''Halothamnus'' are small [shrub](/source/shrub)s or [sub-shrub](/source/sub-shrub)s, two species are [annual](/source/Annual_plant)s. The alternate leaves are sitting without basal narrowing at the branches. They are simple, entire, half-terete or flat and slightly fleshy ([succulent](/source/succulent)).

The bisexual inconspicuous flowers are sitting solitary in the axil of a green [bract](/source/bract) and two green [bracteole](/source/bracteole)s. The five free [tepals](/source/tepals) are green with membranous margins above a transverse line and colourless below. Five [stamens](/source/stamens) arise from a cup-like structure (hypogynous disc) at the base of the flower. One [ovary](/source/ovary) is formed by two [carpels](/source/carpels), with a thick [pistil](/source/pistil), and two [stigma](/source/stigma_(botany))s.

The one-seeded, horizontally flattened fruit keeps being enclosed by the hardening [perianth](/source/perianth). Wings develop from the transverse zone at the outer side of the tepals. Below the wings, the perianth forms a thick and lignified tube with a widened base. Its bottom side has five pits arranged in a ring, surrounded by a rim. These fruit characteristics are essential for the genus ''Halothamnus''.
<gallery>
  file:Halothamnus_lancifolius_fruit.JPG|Fruit (lateral view) of ''Halothamnus lancifolius''
  file:Halothamnus_iranicus_fruit.JPG|Fruit (bottom) of ''Halothamnus iranicus''
</gallery>
thumb|Pollen of ''Halothamnus glaucus'' ssp. ''tianschanicus''
The [pollen](/source/pollen) grains are nearly ball-shaped, 18-38&nbsp;μm in diameter, with 12-29 pores scattered all over the surface (pantoporate), just like it is typically for the goosefoot-family. The species differ from each other in pollen diameter and number of pores, the southern species with the smallest and the northern species with the largest pollen grains.<ref>Gabriele Kothe-Heinrich: ''Revision der Gattung ''Halothamnus'' (Chenopodiaceae)''. Bibliotheca Botanica Bd. 143, Schweizerbart, Stuttgart 1993, {{ISBN|978-3-510-48014-2}}, p.13-14 and p.174-176.
</ref>

== Pollination and dissemination ==
In all species the stamens blossom first, and the stigmas unfold later ([protandry](/source/protandry)). ''Halothamnus subaphyllus'' was proved to be pollinated by insects ([entomophily](/source/entomophily)).<ref>M. M. Iljin: ''K biologii ''[Anabasis aphylla](/source/Anabasis_aphylla)'' L.'' - Sovetsk. Bot. 4: p. 69-76, 1937</ref> There are no observations for the other species, but they are considered to be pollinated by insects, too.

The fruits enclosed by the hardened perianth are dispersed by the wind ([anemochory](/source/anemochory)), lifted up by their wings up to 20&nbsp;mm in diameter.

== Distribution ==
thumb|Distribution area of the genus ''Halothamnus''
The distribution of the genus extends from the [Caucasus Mountains](/source/Caucasus_Mountains) and [Kazakhstan](/source/Kazakhstan) through [Central Asia](/source/Central_Asia), [Southwest Asia](/source/Southwest_Asia) southward to [Somalia](/source/Somalia). The westernmost localities are at the [Sinai Peninsula](/source/Sinai_Peninsula), the easternmost in [Dzungaria](/source/Dzungaria) in [China](/source/China). Most species occur in Iran, [Afghanistan](/source/Afghanistan), and southern Central Asia. All species grow in dry habitats of [desert](/source/desert)s and [semidesert](/source/semidesert)s from 0–2800 m above sea-level. They live on rocky, clayish, or sandy soils; many species tolerate saline conditions.

== Photosynthesis pathway ==
All species of ''Halothamnus'' show leaf anatomy with Kranz arrangement of the ''Salsola''-type. Physiological investigations confirmed that they are all [C4-plants](/source/C4_carbon_fixation).<ref>A. Shomer-Ilan, A. Nissenbaum & Y. Waisel: ''Photosynthetic pathways and the ecological distribution of the Chenopodiaceae in Israel''. - Oecol. (Berlin) 48: p.244-248, 1981.</ref><ref>K. Winter: ''C4 plants of high biomass in arid regions of Asia. Occurrence of C4 photosynthesis in Chenopodiaceae and Polygonaceae from the Middle East and USSR''. - Oecol. (Berlin) 48: p.100-106, 1981.</ref><ref>O. V. Zalenskij & T. Glagoleva: ''Pathway of carbon metabolism in halophytic desert species from Chenopodiaceae''. - Photosynthetica (Prague) 15(2): p.244-255, 1981.</ref>

== Economic importance ==
thumb|''Halothamnus iranicus''
Some species of ''Halothamnus'' are important grazing plants for camels, sheep and goats,<ref name="Kinzikaeva">G. K. Kinzikaeva: ''Aellenia''. - In: P. N. Občinnikov (Hrsg.): ''Flora Tadžikskoj SSR'' 3: p. 419-425. - Leningrad: Nauka, 1968</ref> and are therefore used for the recultivation of pasture,<ref>[http://unesdoc.unesco.org/images/0013/001391/139182e.pdf] ''Combating Desertification – Traditional Knowledge and Modern Technology for the Sustainable Management of Dryland Ecosystems'', UNESCO–MAB Drylands Series No. 4, p.156, 2005</ref> for example ''Halothamnus subaphyllus'', ''Halothamnus auriculus'' and ''Halothamnus glaucus''. ''Halothamnus subaphyllus'' is planted for the stabilisation of mobile sands<ref name="Kinzikaeva" /> and for the production of the medically used [alkaloid](/source/alkaloid) [Salsolin](/source/Salsolin).<ref>A. F. Gammerman u.a.: ''Lekarstvenny rasteniâ SSSR, rastitelnoe syr'e SSSR.'' - Moskva, Leningrad: Izd. Akad. Nauk SSSR, 1957.</ref><ref>S. E. Zemlinskij: ''Lekarstvennye rasteniâ SSSR.'' - Moskva: Medgiz, 1958.</ref> ''Halothamnus somalensis'' is used as medicinal plant against parasitic worms.<ref>F. Dawo & M. Tibbo: [http://www.lrrd.org/lrrd17/6/dawo17068.htm ''Anthelmintic effect of Halothamus somalensis in Arsi-Bale goats'']. In: ''Livestock Research for Rural Development''. Volume 17, Article #68, 2005.</ref> In former times ''Halothamnus subaphyllus'' and ''Halothamnus glaucus'' were used to extract [potash](/source/potash) for making soap.<ref>P. Aellen: ''Chenopodiaceae''. - In: G. Hegi (Hrsg.: K. H. Rechinger):  ''Illustrierte Flora von Mitteleuropa'', 2. Aufl. 3(2): p. 533-747. - Berlin/Hamburg: Parey, 1961.</ref>

== Systematics ==
[[File:Halothamnus glaucus as Kali fruticosum spicatum by Buxbaum.jpg|thumb|The first illustration of a ''Halothamnus'' plant, 1728 as "Kali fruticosum spicatum"  by [J.C. Buxbaum](/source/Johann_Christian_Buxbaum), showing ''[Halothamnus glaucus](/source/Halothamnus_glaucus)'']]
The genus ''Halothamnus'' belongs to the subfamily [Salsoloideae](/source/Salsoloideae) within the family [Amaranthaceae](/source/Amaranthaceae), (formerly [Chenopodiaceae](/source/Chenopodiaceae)). It is grouped to Tribus [Salsoleae](/source/Salsoleae), Subtribus [Sodinae](/source/Sodinae), and is closely related to genus ''[Salsola](/source/Salsola)''.

The genus ''Halothamnus'' was first described in 1845 by [Hippolyte François Jaubert](/source/Hippolyte_Fran%C3%A7ois_Jaubert) and [Édouard Spach](/source/%C3%89douard_Spach) (in ''Illustrationes Plantarum Orientalium'', 2, 50, pl. 136). The type of the genus is ''Halothamnus bottae'', at that time the only species. In 1981, [Victor Petrovič Botschantzev](/source/Victor_Petrovi%C4%8D_Botschantzev) included the genus ''Aellenia'' here and enlarged ''Halothamnus'' to 25 species. After a revision by [Gabriele Kothe-Heinrich](/source/Gabriele_Kothe-Heinrich) (1993), the genus is classified into 2 sections with 21 accepted species:

*Sect. ''Pungentifolia'' Kothe-Heinr.
**'' [Halothamnus beckettii](/source/Halothamnus_beckettii) '' Botsch.
*Sect. ''Halothamnus''
**'' [Halothamnus somalensis](/source/Halothamnus_somalensis) '' (N.E.Br.) Botsch.
**'' [Halothamnus bottae](/source/Halothamnus_bottae) '' Jaub. & Spach - with 2 subspecies
**'' [Halothamnus iranicus](/source/Halothamnus_iranicus) '' Botsch.
**'' [Halothamnus hierochunticus](/source/Halothamnus_hierochunticus) '' (Bornm.) Botsch.
**'' [Halothamnus iliensis](/source/Halothamnus_iliensis) '' (Lipsky) Botsch.
**'' [Halothamnus auriculus](/source/Halothamnus_auriculus) '' (Moq.) Botsch. - with 2 subspecies
**'' [Halothamnus kermanensis](/source/Halothamnus_kermanensis) '' Kothe-Heinr.
**'' [Halothamnus afghanicus](/source/Halothamnus_afghanicus) '' Kothe-Heinr.
**'' [Halothamnus lancifolius](/source/Halothamnus_lancifolius) '' (Boiss.) Kothe-Heinr.
**'' [Halothamnus cinerascens](/source/Halothamnus_cinerascens) '' (Moq.) Kothe-Heinr. - with 2 subspecies
**'' [Halothamnus glaucus](/source/Halothamnus_glaucus) '' (M.Bieb.) Botsch. - with 3 subspecies
**'' [Halothamnus bamianicus](/source/Halothamnus_bamianicus) '' (Gilli) Botsch.
**'' [Halothamnus schurobi](/source/Halothamnus_schurobi) '' (Botsch.)
**'' [Halothamnus turcomanicus](/source/Halothamnus_turcomanicus) '' Botsch.
**'' [Halothamnus ferganensis](/source/Halothamnus_ferganensis) '' Botsch.
**'' [Halothamnus sistanicus](/source/Halothamnus_sistanicus) '' (De Marco & Dinelli) Kothe-Heinr.
**'' [Halothamnus oxianus](/source/Halothamnus_oxianus) '' Botsch.
**'' [Halothamnus seravschanicus](/source/Halothamnus_seravschanicus) '' Botsch.
**'' [Halothamnus iraqensis](/source/Halothamnus_iraqensis) '' Botsch.
**'' [Halothamnus subaphyllus](/source/Halothamnus_subaphyllus) '' (C.Meyer) Botsch. - with 3 subspecies

== References ==
* Gabriele Kothe-Heinrich: ''Revision der Gattung ''Halothamnus'' (Chenopodiaceae)''. Bibliotheca Botanica Bd. 143, Schweizerbart, Stuttgart 1993, {{ISBN|978-3-510-48014-2}} (German)
* Gabriele Kothe-Heinrich: ''Halothamnus''. In: Karl Heinz Rechinger et al. (Edit.): ''Flora Iranica'' 172, ''Chenopodiaceae'': 255-289 - Graz: Akad. Druck 1997, {{ISBN|3-201-00728-5}}
{{Reflist}}

== External links ==
{{Commons category|Halothamnus}}
{{Wikispecies|Halothamnus Jaubert & Spach}}
* [http://www.schweizerbart.de/pubs/isbn/es/bibliothec-3510480147-desc.html Schweizerbart Bibliotheca Botanica Bd. 143 Webpage]
* [http://ww2.bgbm.org/herbarium/Access.cfm?Col=4&IsoCode=all&Fam=CHENOPODIACEAE&SubColl=all&FullNameCache=all&Genus=Halothamnus] Digital herbarium specimens from Herbarium Berlin
* {{NCBI taxid|151227|''Halothamnus'' }}
* [http://www.tropicos.org/Name/40020497 ''Halothamnus'' Jaub. & Spach] at Tropicos

{{Taxonbar|from=Q149213}}
{{Authority control}}

Category:Halothamnus
Category:Amaranthaceae genera

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Adapted from the Wikipedia article [Halothamnus](https://en.wikipedia.org/wiki/Halothamnus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Halothamnus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.