Dysphania Brown, Fl. Nov. Holland.: 411 (1810)

Sukhorukov, Alexander P., Liu, Pei-Liang & Kushunina, Maria, 2019, Taxonomic revision of Chenopodiaceae in Himalaya and Tibet, PhytoKeys 116, pp. 1-141 : 48-49

7. Dysphania Brown, Fl. Nov. Holland.: 411 (1810)

Dysphania littoralis R.Br., Prodr. Fl. Nov. Holland. 412 (1810) (Type).

= Roubieva Moq., Ann. Sci. Nat. Bot., ser. 2(1): 292 (1834); Type: Roubieva multifida (L.) Moq. (≡ Dysphania multifida (L.) Mosyakin & Clemants).

= Ambrina Spach, Hist. Nat. Vég. 5: 295 (1836); Lectotype ( Simón 1996): Ambrina ambrosioides (L.) Spach (≡ Dysphania ambrosioides (L.) Mosyakin & Clemants).

= Botrydium Spach, Hist. Nat. Vég. 5: 298 (1836) nom. illegit., non Wallroth (1815). Lectotype ( Scott 1978): Botrydium aromaticum Spach (= Dysphania botrys (L.) Mosyakin & Clemants);

= Neobotrydium Moldenke, Amer. Midl. Naturalist 35: 330 (1946). Type: Neobotrydium botrys (L.) Moldenke, Amer. Midl. Naturalist 35: 330 (1946) (≡ Dysphania botrys (L.) Mosyakin & Clemants);

Description.

Aromatic annuals or, rarely, perennial herbs and small subshrubs covered with glandular hairs, subsessile yellow or orange glands and simple white hairs. Leaves alternate, entire, lobate or pinnatisect. Inflorescence lax or dense, leafy or not, consisting of cymes that are often reduced to one flower only. Perianth segments 2-5, free or variously connate, the midrib usually with keel. Stamens 1-5. Styles 2, free or basally connate. Fruit subglobose or rarely flattened, 0.3-1.5 mm, its surface reticulate or papillate, rarely smooth, dark coloured but often with whitish longitudinal stripes. Pericarp adjoining the seed coat, rarely bursting, hyaline, consisting of 1-2 very thin layers. Seed reddish or reddish-black, sometimes brown, its testa (outer seed coat layer) lacking vertical tannin-like deposits called “stalactites” in cross-section. Embryo horizontal or vertical, sometimes in both positions within one plant (spatial heterospermy).

More than 50 species worldwide, mostly in the tropics and subtropics. According to the first comprehensive molecular phylogeny (Kadereit et al. in prep.), the genus Dysphania is monophyletic and there is no reason to accept the genera Neobotrydium or Ambrina as was recently proposed ( Zhang and Zhu 2016, Zhu and Sanderson 2017). All native species are closely related and belong to a large clade consisting of Eurasian and African representatives. The mountainous areas of Himalaya and Tibet are now considered one of the four centres of Dysphania diversity, together with Australia, South America and East Tropical Africa ( Sukhorukov and Kushunina 2014, Sukhorukov et al. 2016a). The evident structural fruit and seed dimorphism in Dysphania ( D. tibetica ) is stated here for the first time.