Welwitschiaceae
Welwitschiaceae | |
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Welwitschia mirabilis
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Gnetophyta |
Class: | Gnetopsida |
Order: | Welwitschiales |
Family: | Welwitschiaceae Caruel |
Type genus | |
Welwitschia |
Welwitschiaceae is a family of plants of the order
Taxonomy
German naturalist Friedrich Markgraf coined the name Welwitschiaceae in 1926, which appeared in Die Natürlichen Pflanzenfamilien.[citation needed]
Most recent systems place the Welwitschiaceae in the
Living species
The family contains a single genus and single extant species, Welwitschia mirabilis, which lives in the Kaokoveld Desert of Angola and Namibia in southwestern Africa.[6]
Fossil species
Fossil evidence indicates that members of the Welwitschiaceae were present in South America during the Early Cretaceous (Mesozoic era).[1] Priscowelwitschia austroamericana (initially named Welwitschiella but illegitimate due to the daisy genus Welwitschiella)[7] is a fossil taxon referring to some seedlings with cotyledon leaves. These have many features in common with Welwitschia seedlings.[1] Welwitschiophyllum brasiliense is a taxon known from thick triangular to linear leaves that range from 8.9 to 70 cm long and 2.8–5 cm wide.[1] Welwitschiostrobus murili is a fossil taxon known from some cones that resemble the living Welwitschia, but are longer and thinner.[1]
Jacobson and Lester[8] suggest that these early habitats were more mesic than the current desert conditions, and that the present fragmented and isolated population distribution could be attributed to aridification during the Paleogene, Neogene, and Quaternary, which restricted the plants to locales providing sufficient water for their needs.
References
- ^ PMID 21646150.
- .
- ^ Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 http://www.mobot.org/MOBOT/research/APWeb/
- ^ Chaw S-M., C.L. Parkinson, Y. Cheng, T.M. Vincent and J. D. Palmer (2000) Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers Proceedings of the National Academy of Sciences of the United States of America 97:4086–4091
- PMID 15229124.
- ISBN 9788122407921.
- ^ Dilcher, David L.; Bernardes-De-Oliveira, Mary E.; Pons, Denise; Lott, Terry A. (2005). "Welwitschiaceae from the Lower Cretaceous of northeastern Brazil". American Journal of Botany – Erratum. 92 (12): 1957.[dead link]
- PMID 12816961.