Chenopodium L.

Sukhorukov, Alexander P., Liu, Pei-Liang & Kushunina, Maria, 2019, Taxonomic revision of Chenopodiaceae in Himalaya and Tibet, PhytoKeys 116, pp. 1-141 : 14-15

1. Chenopodium L.

Type.

Chenopodium album L. (typ. cons. prop.)

Notes.

A formal proposal to conserve the name Chenopodium L. with the type Chenopodium album L. has only recently been put forward ( Mosyakin 2015). The conservation of the name with this type would be most desirable to maintain the recent taxonomy of Chenopodium and its relatives, especially Oxybasis .

Description.

Annuals, shrubs, or rarely small trees, covered with bladder hairs. Leaves petiolate, usually lobed or dentate (sometimes entire), very rarely semi-terete. Inflorescences paniculate, composed of small cymose clusters. Flowers sessile and pedicellate, hermaphrodite or some female. Perianth segments 5 (rarely 4), free or basally concrescent, green and unchanging at fruiting. Stamens usually 5, free or basally connate. Stigmas 2, free. Fruit depressed globular, falling off separately or together with perianth. Pericarp mostly thin, hyaline, of 1-2(3) parenchymatous layers, usually with small cylindrical or conical papillae (in dry fruits, the pericarp surface resembles honeycombs, but after soaking, the papillae retrieve their shape). In some species now transferred from Einadia to Chenopodium , the pericarp (at least in most fruits) is fleshy (berry), coloured, and many-layered, but some of the fruits remain dry (heterocarpy). Seeds black or rarely brown with horizontal embryo; the cell walls of testa (outer seed-coat layer) cells in black seeds with vertical stalactites, rarely the stalactites absent (three species from Juan-Fernández Archipelago).

In its current circumscription ( Fuentes et al. 2012), the genus comprises more than 100 species, but the exact number is still unknown. The species are mostly distributed in extratropical parts of the world or in mountainous regions of the tropics.