Dysphania is a plant genus in the family Amaranthaceae, distributed worldwide from the tropics and subtropics to warm-temperate regions.
Description
The species of genus Dysphania are annual plants or short-lived perennials. They are covered with stalked or sessile glandular hairs and therefore with aromatic scent (or malodorous to some people). Some species have uniseriate multicellular trichomes, rarely becoming glabrous. The stems are erect, ascending, decumbent, or prostrate and mostly branched.
The alternate leaves are mostly petiolate, (the upper ones sometimes sessile). The leaf blade is linear, lanceolate, oblanceolate, ovate, or elliptic, often pinnately lobed, with cuneate or truncate base, entire, dentate, or serrate margins.
The inflorescences are terminal, loose, simple or compound cymes or dense axillary glomerules. Bracts are absent or reduced.
Flowers are bisexual (rarely unisexual), with up to five tepals connate only basally or fused to form sac, one to five stamens, and a superior ovary with one to three filiform stigmata.
The fruit is often enclosed in perianth. The membranous pericarp is adherent or nonadherent to the horizontal or vertical, subglobose, or lenticular seed. The seed coat is smooth or rugose. The annular or incompletely annular embryo is surrounding the copious farinose perisperm.
Chromosome numbers
Chromosome numbers reported are 2n=16, 18, 32, 36, and 48.[1]
Photosynthesis pathway
All species of genus Dysphania are C3 plants with normal leaf anatomy.[2]
Distribution
The genus Dysphania is distributed worldwide from the tropics and subtropics to warm-temperate regions. In Europe, the species are native, archaeophytes, or naturalized, in the northern regions absent or rarely adventive.[3]
Dysphania was first published in 1810 by Robert Brown in Prodromus Florae Novae Hollandiae, p. 411-412.[4] Type species is Dysphania littoralis R.Br..
The genus Dysphania primarily comprised 7-10 Australian species. Sometimes they were grouped as an own family, Dysphaniaceae Pax & Hoffmann, or even regarded as members of families Illecebraceae and Caryophyllaceae. In 2002, Sergei L. Mosyakin & Steven E. Clemants extended the genus for the glandular species of Chenopodium subgenus Ambrosia A.J.Scott.
Synonyms for Dysphania R.Br. are Neobotrydium Moldenke, Roubieva Moq. and Teloxys Moq..
The genus Dysphania consists of four sections with about 40 species:[5]
Dysphania sect. Adenois (Moq.) Mosyakin & Clemants: 15 species, native in South and Middle America, now distributed worldwide from the tropics to warm-temperate regions:
Dysphania ambrosioides (L.) Mosyakin & Clemants (Syn.: Chenopodium ambrosioides L., Dysphania anthelmintica (L.) Mosyakin & Clemants), Epazote, Mexican-tea: native in North- and South America, naturalized in other continents.
Dysphania sect. Botryoides (C.A.Mey.) Mosyakin & Clemants: with 3 subsections:
Dysphania sect. Botryoides subsect. Botrys (Aellen & Iljin) Mosyakin & Clemants: with 9 species, worldwide, native in southern North America, northern South America, southern Eurasia and Africa.
Dysphania botrys (L.) Mosyakin & Clemants, Syn.: Chenopodium botrys L.), Jerusalem-oak, feather-geranium: native from Middle Europa to China (Xinjiang), naturalized or cultivated in other temperate regions.
Dysphania nepalensis (Colla) Mosyakin & Clemants (Syn.: Chenopodium nepalense Colla), in Central Asia
Dysphania procera (Hochst. ex Moq.) Mosyakin & Clemants (Syn.: Chenopodium procerum Hochst. ex Moq.)
Dysphania pseudomultiflora (Murr) Verloove & Lambinon (Syn.: Chenopodium foetidum Schrad. subsp. pseudomultiflorum Murr): In South Africa.
Dysphania congolana (Hauman) Mosyakin & Clemants (Syn.: Chenopodium glaucum L. var. congolanum Hauman, Chenopodium congolanum (Hauman) Brenan), in Africa
Steven E. Clemants & Sergei L. Mosyakin (2003): Dysphania - online. In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico. Volume 4: Magnoliophyta: Caryophyllidae, part 1. Oxford University Press, New York, ISBN0-19-517389-9, p. 267. (chapters description, distribution, systematics)
Sergei L. Mosyakin, Steven E. Clemants (2008): Further Transfers of glandular-pubescent species from Chenopodium subg. Ambrosia to Dysphania (Chenopodiaceae). In: Journal of the Botanical Research Institute of Texas Vol.2, Nr. 1, p. 425–431. (chapter systematics)
Gelin Zhu, Sergei L. Mosyakin & Steven E. Clemants (2003): Chenopodiaceae: Dysphania – online. In: Wu Zhengyi, Peter H. Raven, Deyuan Hong (Hrsg.): Flora of China. Volume 5: Ulmaceae through Basellaceae. Science Press u.a., Beijing u.a., ISBN1-930723-27-X, p. 376. (chapter description, vernacular name)
^ abGudrun Kadereit, Evgeny V. Mavrodiev, Elizabeth H. Zacharias, Alexander P. Sukhorukov (2010): Molecular phylogeny of Atripliceae (Chenopodioideae, Chenopodiaceae): Implications for systematics, biogeography, flower and fruit evolution, and the origin of C4 Photosynthesis. In: American Journal of Botany, 97(10), p. 1664–1687.
^Pertti Uotila (2011): Chenopodiaceae (pro parte majore). – In: Euro+Med Plantbase – the information resource for Euro-Mediterranean plant diversity. Dysphania. Euro+Med Plantbase, retrieved 30 November 2011.