Gomphrenoideae

The Gomphrenoideae are a subfamily of the Amaranthaceae.

Gomphrenoideae
Gomphrena globosa
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Amaranthaceae
Subfamily: Gomphrenoideae
Schinz
Genera

about 13 genera, see text

The stamens have anthers with only one lobe (locule) and two pollen sacs. Many species show C4-photosynthesis pathway.[1]

The center of diversity lies in Central America, Mexico and the dry forests and thorn bush savannas of South America.[2]

Systematics

The subfamily Gomphrenoideae was first published in 1893 by Hans Schinz (in: Engler und Prantl (Eds.): Die Natürlichen Pflanzenfamilien vol. 3, 1a, p. 97).

According to phylogenetic research by Sanchez Del-Pino (2009), the subfamily Gomphrenoideae Schinz is regarded as a monophyletic taxon with 19 genera and about 300-400 species. The traditional classification with two tribes (Gomphreneae and Pseudoplantageae) does not reflect the phylogenetic relationship in this group. Three clades can be recognized.:[1]

Iresinoids
  • Irenella Suess., with only one species:
    • Irenella chrysotricha Suess., in rain forests of Ecuador. Phylogenetically, it falls within Iresine.
  • Iresine P.Browne (Syn.: Dicraurus Hook. f.): 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. (Syn.: Brandesia Mart.): 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.

C4 carbon fixation evolved independently in the genera Alternathera, which also contains C3 and C3–C4 intermediate species, and Tidestromia.[3][4]

Gomphrenoids
  • Blutaparon Raf. (Syn.: Philoxerus R.Br.): with about 5 species at shores of North and Middle America, West Africa, Micronesia and Japan, for example:
  • Froelichia Moench: with about 12 species in America.
  • Froelichiella R.E.Fr., with only one species:
    • Froelichiella grisea R.E.Fr. in Brasília.
  • Gomphrena L. (Syn.: Bragantia Vand.): with about 90 species in America and about 30 species in Australia. This genus is polyphyletic, so taxonomical changes have to be expected.[1]
  • Gossypianthus Hook.: with 2 species in southern North America.
  • Guilleminea Kunth (Syn.: Brayulinea Small)
  • Hebanthe Mart.: with about 7 species in tropical America.
  • Hebanthodes Pedersen, with only one species:
    • Hebanthodes peruviana Pedersen in Peru.
  • Lithophila Sw., with 2 species on Galapagos and the Caribic
  • Pfaffia Mart.: with about 35 species in tropical America.
  • Pseudogomphrena R.E.Fr.,with only one species:
    • Pseudogomphrena scandens R.E.Fr. in Brasília.
  • Pseudoplantago Suess.: with one species in Venezuela and one in Argentina.
  • Quaternella Pedersen: with 3 species in Brasília.
  • Xerosiphon Turcz.: with about 2 species in Brasília.

One large clade within this group, containing the genera Froelichia, Guilleminea, Blutaparon, some Gomphrena species, and probably Gossypianthus and Lithophila, has acquired the C4 carbon fixation pathway.[3][4] Some of these C4 species occur at unusually high altitudes in the Andes, in cooler conditions than their C3 relatives.[5]

Photographs

References
  1. Ivonne Sánchez del-Pino, Thomas Borsch & Timothy J. Motley (2009): trnL-F and rpl16 Sequence Data and Dense Taxon Sampling Reveal Monophyly of Unilocular Anthered Gomphrenoideae (Amaranthaceae) and an Improved Picture of Their Internal Relationships, In: Systematic Botany, Volume 34 (1), p. 57-67. doi:10.1600/036364409787602401
  2. Kai Müller & Thomas Borsch (2005): Phylogenetics of Amaranthaceae using matK/trnK sequence data – evidence from parsimony, likelihood and Bayesian approaches, In: Annals of the Missouri Botanical Garden, 92, p. 66-102.
  3. Sage, R.F. (2016). "A portrait of the C4 photosynthetic family on the 50th anniversary of its discovery: species number, evolutionary lineages, and Hall of Fame". Journal of Experimental Botany. 67 (14): 4039–4056. doi:10.1093/jxb/erw156. ISSN 0022-0957. PMID 27053721.
  4. Sage, R.F.; Sage, T.L.; Pearcy, R.W.; Borsch, T. (2007). "The taxonomic distribution of C4 photosynthesis in Amaranthaceae sensu stricto". American Journal of Botany. 94 (12): 1992–2003. doi:10.3732/ajb.94.12.1992. ISSN 0002-9122. PMID 21636394.
  5. Bena, M.J.; Acosta, J.M.; Aagesen, Lone (2017). "Macroclimatic niche limits and the evolution of C4 photosynthesis in Gomphrenoideae (Amaranthaceae)". Botanical Journal of the Linnean Society. 184 (3): 283–297. doi:10.1093/botlinnean/box031. ISSN 0024-4074.
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