Dysphania

Dysphania R. Brown

In its original sense Dysphania was a vaguely circumscribed Australian genus of 7-10 species (Aellen 1930). Mosyakin & Clemants (2002, 2008) considerably expanded Dysphania and it now includes all gland-dotted taxa that were formerly accommodated in Chenopodium. As such, Dysphania provisionally counts ca. 32 species and occurs in tropical, subtropical and warm-temperate regions of the world. In few years of time this new generic concept has become widely accepted (Mabberley 2008) and it was recently also confirmed by molecular phylogenetic studies (Kadereit & al. 2010).

The Australian species of Dysphania sect. Orthospora – here represented by D. carinata, D. cristata and D. pumilio – form a taxonomically difficult group in which hybridisation sometimes occurs. This might have blurred the boundaries between some species. Some Belgian collections are more or less intermediate and possibly represent hybrids (especially Dysphania xbontei (Aell.) Stace, the hybrid of D. carinata and D. cristata).  

1. Inflorescence composed of lax, dichasial cymes. Leaves usually pinnatifid. Seeds mostly horizontal === 2

1. Inflorescence composed of dense, sessile glomerules. Leaves dentate to sinuate. Seeds vertical or horizontal === 3

2. Perianth segments not keeled, with stipitate glands. Inflorescence usually leafless or with small leaf-like bracts in proximal part) === Dysphania botrys

2. Perianth segments distinctly keeled, with (sub-) sessile glands. Inflorescence usually leafy almost to the top === D. schraderiana

3. Plant prostrate to ascending. Leaves less than 30 mm long, usually sinuate. Perianth segments becoming indurate and white at maturity === 4

3. Plant erect, up to 80 (-120) cm tall. Largest leaves more than 30 mm long, usually dentate. Perianth segments green and herbaceous at maturity === 5

4. Perianth segments keeled on the back === D. carinata

4. Perianth segments rounded on the back === D. pumilio

5. Leaflike bracts much reduced, up to as long as or barely longer than glomerules, inflorescence not leafy === D. anthelmintica

5. Leaflike bracts much longer than the glomerules, inflorescence leafy === D. ambrosioides

Additional aliens: Dysphania cristata (F. Muell.) Mosyakin et Clemants (syn.: Chenopodium cristatum (F. Muell.) F. Muell.) (Aus., wool alien), D. glomulifera (Nees) P.G. Wilson (syn.: D. myriocephala Benth., Chenopodium myriocephalum (Benth.) Aellen) (Aus., wool alien), D. multifida (L.) Mosyakin et Clemants (syn.: Chenopodium multifidum L.) (S-Am., wool alien) and D. pseudomultiflora (J. Murr) Verloove et Lambinon (syn.: Chenopodium pseudomultiflorum (J. Murr) Uotila).

 


Literature:

Aellen P. (1930) Die systematische Stellung und Gliederung der R. Brownischen Gattung Dysphania. Bot. Jahrb. Syst. 63: 483-490.

Kadereit G., Mavrodiev E.V., Zacharias E.H. & Sukhorukov A. (2010) Molecular phylogeny of Atripliceae (Chenopodioideae, Chenopodiaceae): implications for systematics, biogeography, flower and fruit evolution, and the origin of C4 photosynthesis.Am. J. Bot. 97(10): 1664-1687.

Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.

Mosyakin S.L. & Clemants S.E. (2002) New nomenclatural combinations in Dysphania R.Br. (Chenopodiaceae): taxa occurring in North America. Ukr. Botan. Journ. 59: 380-385.

Mosyakin S.L. & Clemants S.E. (2008) Further transfers of glandular-pubescent species from Chenopodium subg. Ambrosia to Dysphania (Chenopodiaceae). J. Bot. Res. Inst. Texas 2(1): 425-431.

Simón L.E. (1996) Notas sobre Chenopodium L. subgen. Ambrosia A.J. Scott (Chenopodiaceae). 1. Taxonomía. 2. Fitogeografía: áreas disyuntas. Anales Jard. Bot. Madrid 54: 137-148.

Uotila P. (2013) Dysphania sect. Botryoides (Amaranthaceae s. lat.) in Asia. Willdenowia 43(1): 65-80. [available online at: http://www.ingentaconnect.com/content/bgbm/will/2013/00000043/00000001/a...

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith