Dysphania (plant)


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 oder sessile glandular hairs and therefore with aromatic scent. 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 leaf blade is linear, lanceolate, oblanceolate, ovate, or elliptic, often pinnately lobed, with cuneate or truncate base, anentire, 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, 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.
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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

numbers reported are 2n=16, 18, 32, 36, and 48.

Photosynthesis pathway

All species of genus Dysphania are C3 plants with normal leaf anatomy.

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.

Systematics

The genus Dysphania belongs to the tribe Dysphanieae in the subfamily Chenopodioideae within the plant family Amaranthaceae. According to phylogenetic research, it is related to genera Suckleya and Cycloloma.
Dysphania was first published in 1810 by Robert Brown in Prodromus Florae Novae Hollandiae, p. 411-412. 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:
Excluded species: Teloxys aristata.

Usage

or Mexican tea and American wormseed are medicinal herbs. Epazote is used as a tisane and as an insecticide. Some species of Dysphania are used as dye.