Southern beech

''Nothofagus'', also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America (Chile, Argentina) and Australasia (east and southeast Australia, New Zealand, New Guinea, and New Caledonia). The species are ecological dominants in many temperate forests in these regions. Some species are reportedly naturalised in Germany and Great Britain.Kew World Checklist of Selected Plant Families
/ref> The genus has a rich fossil record of leaves, cupules, and pollen, with fossils extending into the late Cretaceous period and occurring in Australia, New Zealand, Antarctica, and South America.

Description

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.

Reproduction

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''.

In the past, they were included in the family Fagaceae, but genetic tests revealed them to be genetically distinct, and they are now included in their own family, Nothofagaceae.

Species list

The following is a list of species, hybrids and varieties accepted by the Plants of the World Online as at April 2020:
*'' Nothofagus aequilateralis'' (Baum.-Bod.) Steenis (New Caledonia)
*'' Nothofagus alessandri'' Espinosa (Central Chile)
*'' Nothofagus alpina'' (Poepp. & Endl.) Oerst. (Argentina South, Chile Central, Chile South)
*''Nothofagus antarctica'' (G.Forst.) Oerst. (Argentina South, Chile Central, Chile South)
*'' Nothofagus balansae'' (Baill.) Steenis (New Caledonia)
*'' Nothofagus baumanniae'' (Baum.-Bod.) Steenis (New Caledonia)
*'' Nothofagus betuloides'' (Mirb.) Oerst. (Argentina South, Chile South)
*'' Nothofagus brassii'' Steenis (New Guinea)
*''Nothofagus carrii'' Steenis (New Guinea)
*''Nothofagus cliffortioides'' (Hook.f.) Oerst. (New Zealand North, New Zealand South)
*''Nothofagus codonandra'' (Hook.f.) Oerst. (New Caledonia)
*''Nothofagus crenata'' Steenis (New Guinea)
*''Nothofagus cunninghamii'' (Hook.f.) Oerst. (Tasmania, Victoria)
*''Nothofagus discoidea'' (Baum.-Bod.) Steenis (New Caledonia)
*''Nothofagus dombeyi'' (Mirb.) Oerst. (Argentina South, Chile Central, Chile South)
*''Nothofagus flaviramea'' Steenis (New Guinea)
*'' Nothofagus fusca'' (Hook.f.) Oerst. (New Zealand North, New Zealand South)
*'' Nothofagus glauca'' (Phil.) Krasser (Chile Central)
*''Nothofagus grandis'' Steenis (New Guinea)
*'' Nothofagus gunnii'' (Hook.f.) Oerst. (Tasmania)
*'' Nothofagus macrocarpa'' (A.DC.) F.M.Vázquez & R.A.Rodr. (Chile Central)
*''Nothofagus menziesii'' (Hook.f.) Oerst. (New Zealand North, New Zealand South)
*'' Nothofagus moorei'' .Muell.) Krasser (New South Wales, Queensland)
*''Nothofagus nitida'' (Phil.) Krasser (Chile South)
*''Nothofagus nuda'' Steenis (New Guinea)
*''Nothofagus obliqua'' (Mirb.) Oerst. (Argentina South, Chile Central, Chile South)
*''Nothofagus perryi'' Steenis (New Guinea)
*''Nothofagus pseudoresinosa'' Steenis (New Guinea)
*'' Nothofagus pullei'' Steenis (New Guinea)
*''Nothofagus pumilio'' (Poepp. & Endl.) Krasser (Argentina South, Chile Central, Chile South)
*''Nothofagus resinosa'' Steenis (New Guinea)
*''Nothofagus rubra'' Steenis (New Guinea)
*''Nothofagus rutila'' Ravenna (Chile Central)
*''Nothofagus solandri'' (Hook.f.) Oerst. (New Zealand North, New Zealand South)
*'' Nothofagus starkenborghii'' Steenis (Bismarck Archipelago, New Guinea)
*'' Nothofagus stylosa'' Steenis (New Guinea)
*'' Nothofagus truncata'' (Colenso) Cockayne (New Zealand North, New Zealand South)
*''Nothofagus womersleyi'' Steenis (New Guinea)
*''Nothofagus × apiculata'' (Colenso) Cockayne (New Zealand North, New Zealand South)
*''Nothofagus × blairii'' Kirk (New Zealand North, New Zealand South)
*''Nothofagus × dodecaphleps'' Mike L.Grant & E.J.Clement
*''Nothofagus × eugenananus'' Gilland.
*''Nothofagus × leoni'' Espinosa (Chile Central)
*''Nothofagus × solfusca'' Allan (New Zealand North)
*''Nothofagus'' var. ''crenata'' Steenis (New Guinea)
*''Nothofagus'' var. ''sapeii'' Steenis (New Guinea)

Sub-genera

Four sub-genera are recognized, based on morphology and DNA analysis:
* Subgenus ''Fuscospora'', six species (''N. alessandri, N. cliffortioides, N. fusca, N. gunnii, N. solandri'', and ''N. truncata'') in New Zealand, Tasmania, and southern South America.
* Subgenus ''Lophozonia'', seven species (''N. alpina, N. cunninghamii, N. glauca, N. macrocarpa, N. menziesii, N. moorei'', and ''N. obliqua'') in New Zealand, Australia, and southern South America.
* Subgenus ''Nothofagus'', five species (''N. antarctica, N. betuloides, N. dombeyi, N. nitida'', and ''N. pumilio'') in southern South America.
* Subgenus ''Brassospora'' (or ''Trisyngyne''), 25 species (''N. aequilateralis, N. balansae, N. baumanniae, N. bernhardii, N. brassii, N. carrii, N. codonandra, N. cornuta, N. crenata, N. decipiens, N. discoidea, N. dura, N. eymae, N. flaviramea, N. grandis, N. nuda, N. perryi, N. pseudoresinosa, N, pullei, N. recurva, N. resinosa, N. rubra, N. starkenborghii, N. stylosa'', and ''N. womersleyi'') in New Guinea and New Caledonia.

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 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)

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. 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.

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. A diversity of Antarctic ''Nothofagus'' species are known from the Zamek Hill assemblage of King George Island. ''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