Shoots, leaves, and cupules of N. obliqua
Nothofagus, also known as the southern beeches, is a genus of about 35 species of trees and shrubs native to the temperate oceanic to tropical Southern Hemisphere in southern South America (Chile, Argentina) and Australasia (east & southeast Australia, Tasmania, New Zealand, New Guinea and New Caledonia). Fossils have recently been found in Antarctica[1].
In the past they were included in the family Fagaceae, but genetic tests by the Angiosperm Phylogeny Group revealed them to be genetically distinct, and they are now included in a family their own, the Nothofagaceae.
The leaves are toothed or entire, evergreen or deciduous. The fruit is a small, flattened or triangular nut, borne in cupules containing 2-7 nuts.
Nothofagus species are used as food plants by the larva of hepialid moths of the genus Aenetus including A. eximia and A. virescens.
Many individuals are extremely old, and at one time it was believed that some populations could not reproduce in present-day conditions at the location where they were growing, except by suckering (clonal reproduction), being remnant forest from a cooler time. It has since been shown that sexual reproduction may occur [1], but distribution in cool, isolated high-altitude environments at temperate and tropical latitudes is consistent with the theory that the species was more prolific in a cooler age. [2] The pattern of distribution around the southern Pacific rim suggests that the dissemination of the genus dates to the time when Antarctica, Australia and South America were connected, a common land-mass referred to as Gondwanaland. [3]
Taxonomy
The genus is classified in the following sections:[2]
- Sect. Brassospora (type Nothofagus brassi)
- Sect. Fuscospora (type Nothofagus fusca)
- Sect. Lophozonia (type Nothofagus menziesii)
- Sect. Nothofagus (type Nothofagus antarctica)
References
- ^ Li, HM., and Zhou, ZK. 2007. Fossil nothofagaceous leaves from the Eocene of western Antarctica and their bearing on the origin, dispersal and systematics of Nothofagus. Science in China. 50(10): 1525-1535.
- ^ Nothofagus website (in French)
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