Nothofagus

The leaves are toothed or entire, evergreen or deciduous. The fruit is a small, flattened or triangular nut, borne in cupules containing one to seven nuts. Many individual trees are extremely old, and at one time, some populations were thought to be unable to reproduce in present-day conditions where they were growing, except by suckering (clonal reproduction), being remnant forest from a cooler time. Sexual reproduction has since been shown to be possible. ==Taxonomy==

The genus Nothofagus was first formally described in 1850 by Carl Ludwig Blume who published the description in his book Museum botanicum Lugduno-Batavum, sive, Stirpium exoticarum novarum vel minus cognitarum ex vivis aut siccis brevis expositio et descriptio. Nothofagus means "false beech", which Blume chose to indicate that Nothofagus species were different from beeches in the Northern Hemisphere. In the past, they were included in the family Fagaceae, but genetic tests revealed them to be genetically distinct, This taxonomy was introduced in 1962 by Russian botanist and palynologist Ludmila Andreyevna Kuprianova, who used pollen traits to erect Nothofagaceae. A study in 1999 found that the pollen exine ultrastructure of Nothofagus differs from that of Fagaceae genera by its thickness, type of aperture, and ornamentation, reinforcing the placement of Nothofagus in its own family. Species list The following is a list of the 38 species and 4 hybrids accepted by Plants of the World Online : In 2013, Peter Brian Heenan and Rob D. Smissen proposed splitting the genus into four, turning the four recognized subgenera into the new genera Fuscospora, Lophozonia and Trisyngyne, with the five South American species of subgenus Nothofagus remaining in genus Nothofagus. The two authors posited that the four clades have evolutionary equivalence with other Fagales genera, and that the morphological and molecular differences are pronounced enough to raise the subgenera a rank. The proposed new genera are not accepted at the World Checklist of Selected Plant Families. Extinct species The following additional species are listed as extinct: • †Nothofagus australis (Argentina, Early Oligocene-Early Miocene) • †Nothofagus balfourensis (Tasmania, Late Oligocene-Early Miocene) • †Nothofagus beardmorensis (Antarctica, Late Pliocene) • †Nothofagus bulbosa (Tasmania, Early Oligocene) • †Nothofagus cethanica (Tasmania, Early Oligocene) • †Nothofagus cooksoniae (Tasmania, Early Oligocene) • †Nothofagus crenulata (Argentina, Mid Oligocene-Early Miocene) • †Nothofagus cretacea (Antarctica, Late Cretaceous) • †Nothofagus densinervosa (Argentina, Mid Oligocene-Early Miocene) • †Nothofagus elongata (Argentina, Early Oligocene-Early Miocene) • †Nothofagus glandularis (Tasmania, Mid Oligocene-Early Miocene) • †Nothofagus glaucifolia (Antarctica, Late Cretaceous) • †Nothofagus lanceolata (Argentina, Late Oligocene-Early Miocene) • †Nothofagus lobata (Tasmania, Early Oligocene) • †Nothofagus magelhaenica (Argentina, Early Oligocene-Early Miocene) • †Nothofagus magellanica (Argentina, Late Oligocene-Mid Miocene) • †Nothofagus maideni (Tasmania, Early Oligocene-Mid Miocene) • †Nothofagus microphylla (Tasmania, Late Oligocene-Mid Miocene) • †Nothofagus mucronata (Tasmania, Early Oligocene) • †Nothofagus muelleri (New South Wales, Late Eocene) • †Nothofagus novae-zealandiae (New Zealand, Mid-Late Miocene) • †Nothofagus pachyphylla (Tasmania, Early Pleistocene) • †Nothofagus palustris (New Zealand, Late Oligocene-Early Miocene) • †Nothofagus peduncularis (Tasmania, Early Oligocene) • †Nothofagus robusta (Tasmania, Early Oligocene) • †Nothofagus serrata (Tasmania, Early Oligocene) • †Nothofagus serrulata (Argentina, Mid Oligocene-Early Miocene) • †Nothofagus simplicidens (Argentina, Mid Oligocene-Early Miocene) • †Nothofagus smithtonensis (Tasmania, Early Oligocene) • †Nothofagus tasmanica (Tasmania, Eocene-Early Oligocene) • †Nothofagus ulmifolia (Antarctica, Late Cretaceous) • †Nothofagus variabilis (Argentina, Oligocene) • †Nothofagus zastawniakiae (Antarctica, Late Cretaceous) Evolutionary history Nothofagus first appeared in Antarctica during the early Campanian stage (83.6 to 72.1 million years ago) of the Late Cretaceous. During the Campanian Nothofagus diversified and became dominant within Antarctic ecosystems, with the appearance of all four modern subgenera by the end of the stage. Nothofagus shows a progressive decline in the Antarctic pollen record through the Maastrichtian, before substantially recovering after the Cretaceous-Paleogene boundary. Nothofagus persisted in Antarctica deep into the Cenozoic, despite the increasingly inhospitable conditions, with the final records from the late Neogene, around 15-5 million years old, which were small tundra-adapted prostrate shrubs, similar to Salix arctica (Arctic willow). Nothofagus had already spread into Australia and New Zealand by the mid Campanian, and first appeared in southern South America during the late Campanian. During the Paleocene and Eocene their distribution in South America was mostly restricted to southern Patagonia, before reaching a peak abundance during the Miocene. Their distribution contracted westwards during the late Miocene due to the aridification of Patagonia. Although the genus now mostly occurs in cool, isolated, high-altitude environments at temperate and tropical latitudes, the fossil record shows that it survived in climates that appear to be much warmer than those that Nothofagus now occupies. : Australia, New Guinea, New Zealand, New Caledonia, Argentina, and Chile. ==Distribution==

The pattern of distribution around the southern Pacific Rim suggests the dissemination of the genus dates to the time when Antarctica, Australia, and South America were connected in a common land-mass or supercontinent referred to as Gondwana. More recent studies suggest that the Antarctic land bridge likely played a major role in the dispersal of the genus between these continents. However, genetic evidence using molecular dating methods has been used to argue that the species in New Zealand and New Caledonia evolved from species that arrived in these landmasses by dispersal across oceans. Uncertainty exists in molecular dates and controversy rages as to whether the distribution of Nothofagus derives from the break-up of Gondwana (i.e. vicariance), or if long-distance dispersal has occurred across oceans. In South America, the northern limit of the genus can be construed as La Campana National Park and the Vizcachas Mountains in the central part of Chile. ==Ecology==

Nothofagus species are used as food plants by the larvae of hepialid moths of the genus Aenetus, including A. eximia and A. virescens. Zelopsis nothofagi is a leaf hopper, endemic to New Zealand, which is found on Nothofagus. Cyttaria is genus of ascomycete fungi found on or associated with Nothofagus in Australia and South America. Misodendrum are specialist parasitic plants found on various species of Nothofagus in South America. The species of subgenus Brassospora are evergreen, and distributed in the tropics of New Guinea, New Britain, and New Caledonia. In New Guinea and New Britain Nothofagus is characteristic of lower montane rain forests between elevation, occurring infrequently at elevations as low as , and in upper montane forests between elevation. Nothofagus is most commonly found above the Castanopsis-Lithocarpus zone in the lower montane forests, and below the conifer-dominated upper montane forests. Nothofagus grows in mixed stands with trees of other species or in pure stands, particularly on ridge crests and upper slopes. The Central Range has the greatest diversity of species, with fewer species distributed among the mountains of western and northern New Guinea, New Britain, and Goodenough and Normanby islands. The New Caledonian species are endemic to the main island (Grand Terre), most commonly on soils derived from ultramafic rocks between elevation. They occur in isolated stands, forming a low or stunted and irregular and fairly open canopy. The conifers Agathis and Araucaria are sometimes present as emergents, rising above the Nothofagus canopy. Southernmost tree on earth The southernmost tree in the world is reportedly an N. betuloides, living in a stand on the windswept island of Isla Hornos, at the southern edge of the Tierra del Fuego archipelago. It is believed to be 41. ==References==