Gomphrenoideae


The Gomphrenoideae are a subfamily of the Amaranthaceae.
The stamens have anthers with only one lobe and two pollen sacs. Many species show C4-photosynthesis pathway.
The center of diversity lies in Central America, Mexico and the dry forests and thorn bush savannas of South America.

Systematics

The subfamily Gomphrenoideae was first published in 1893 by Hans Schinz.
According to phylogenetic research by Sanchez Del-Pino, the subfamily Gomphrenoideae Schinz is regarded as a monophyletic taxon with 19 genera and about 300-400 species. The traditional classification with two tribes does not reflect the phylogenetic relationship in this group. Three clades can be recognized.:

Iresinoids

Irenella Suess., with only one species:
  • * Irenella chrysotricha Suess., in rain forests of Ecuador. Phylogenetically, it falls within Iresine.Iresine P.Browne : with about 45 species in North and South America.Woehleria Griseb.: with only one species
  • * Woehleria serpyllifolia Griseb., on mountain coasts of Cuba. Phylogenetically, it falls within Iresine.
This is the sister clade of the two other clades.

Alternantheroids

Alternanthera Forssk. : with about 100-200 species, mainly in America, also in Africa and Australia.Pedersenia Holub: with about 10 species in tropical America.Tidestromia Standl.: with about 6 species in deserts of southern North America.
carbon fixation evolved independently in the genera Alternathera, which also contains and – intermediate species, and Tidestromia.

Gomphrenoids

Blutaparon Raf. : with about 5 species at shores of North and Middle America, West Africa, Micronesia and Japan, for example:
One large clade within this group, containing the genera Froelichia, Guilleminea, Blutaparon, some Gomphrena species, and probably Gossypianthus and Lithophila, has acquired the carbon fixation pathway. Some of these species occur at unusually high altitudes in the Andes, in cooler conditions than their relatives.