''Lithocarpus'' is a genus in the
beech
Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...
family,
Fagaceae
The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergre ...
. Trees in this genus are commonly known as the stone oaks and differ from ''
Quercus
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...
'' primarily because they produce insect-pollinated flowers on erect
spikes and the female flowers have short
styles with punctate
stigmas. At current, around 340 species have been described, mostly restricted to
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...
. Fossils show that ''Lithocarpus'' formerly had a wider distribution, being found in North America and Europe during the
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
to
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...
epochs. The species extend from the foothills of the
Hengduan Mountains, where they form dominant stands of trees, through Indochina and the Malayan Archipelago, crossing
Wallace's Line
The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by English biologist Thomas Henry Huxley that separates the biogeographical realms of Asia and Wallacea, a tran ...
and reaching
Papua. In general, these trees are most dominant in the uplands (more than above sea level) and have many ecological similarities to the
Dipterocarpaceae
Dipterocarpaceae is a family of 16 genera and about 695 known species of mainly tropical lowland rainforest trees. The family name, from the type genus ''Dipterocarpus'', is derived from Greek (''di'' = two, ''pteron'' = wing and ''karpos'' = fru ...
, the dominant lowland tree group.
[ These trees are intolerant of seasonal droughts, not being found on the ]Lesser Sunda Islands
The Lesser Sunda Islands or nowadays known as Nusa Tenggara Islands ( id, Kepulauan Nusa Tenggara, formerly ) are an archipelago in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up t ...
, despite their ability to cross numerous water barriers to reach Papua.
The North American tanoak or tanbark oak (''Notholithocarpus densiflorus'') was previously included in this genus but recent evidence indicates the similarities in flower and fruit morphology are due to convergent evolution. Both genetic and morphological evidence demonstrate that the tanoak is a distant relative to Asian stone oaks and, therefore tanoak has been moved into a new genus, '' Notholithocarpus''.[
''Lithocarpus'' trees are ]evergreen
In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s with leathery, alternate leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
, the margins of which are almost always entire, rarely toothed. The seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
is a nut
Nut often refers to:
* Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds
* Nut (hardware), fastener used with a bolt
Nut or Nuts may also refer to:
Arts, entertainment, and media Com ...
similar to an oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
acorn
The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally
two seeds), enclosed in a tough, leathery shell, and borne ...
with a cupule enclosing the basal part of the fruit. Cupules of stone oaks demonstrate a much wider variety in the type and arrangement of lamellae and scales on the outside of the cupule, with some of them completely enclosing the nut, even becoming irregularly dehiscent
Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...
in a few species. The seeds are often protected by a hard woody shell (hence the genus name, from Greek , , "stone" and , , "seed"). In some sections of the genus, the seed is embedded in the basal material of the fruit which becomes highly lignified
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity ...
and hard, lending greater mechanical protection to the seed,[ creating a novel type of fruit.][ The kernel is edible in some species (e.g. '']Lithocarpus edulis
''Lithocarpus edulis'', the Japanese stone oak, is a species of Lithocarpus, stone-oak native to Japan. It is an evergreen tree growing up to 15 metres tall. The nuts are edible for people but taste bitter. The nuts contain tannins, however soak ...
''), but inedible, and very bitter, in others.
Several of the species are very attractive ornamental trees, used in park
A park is an area of natural, semi-natural or planted space set aside for human enjoyment and recreation or for the protection of wildlife or natural habitats. Urban parks are urban green space, green spaces set aside for recreation inside t ...
s and large garden
A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both ...
s in warm temperate and subtropical areas.
Classification
In 1948, Aimee Camus produced a comprehensive treatment of the two major genera in the family,[ given the specimens available to her at the Natural History Museum in Paris. Because of the many collections available from the French colonies in subtropical and tropical Indochina, she worked extensively with stone oaks from the region. Most importantly, she provided the only existing infrageneric structure within the genus but unfortunately, many of the species from the Malesian region, south of the Isthmus of Kra, are not incorporated into this system.
Her classification system included 13 subgenera, including the subgenus ''Pasania'' which is by far the largest division within the genus. About 100 Asian species were treated separately in ''Pasania'', at the genus level, and occasionally the old name persists on some herbarium sheets that have not been annotated. Several of the other subgenera possess fewer than ten species and have distinctive morphologies. Few of the Malesian species are treated in Camus' system and Soepadmo, who wrote the Flora Malesiana treatment,][ made no attempt to update or integrate these species into Camus' system, therefore a lot of work obviously remains to be done. Camus' system was highly detailed, as three levels of organization are recognized below the subgenus, but the classification is not systematic at the lowest level.
List of subgenera (No. of species in Camus' treatment): ''Castanicarpus'' (1); ''Corylopasania'' (2); ''Cryptostylis'' (1); ''Cyclobalanus'' (58); ''Cyrtobalanus'' (1); ''Eulithocarpus'' (11); ''Gymnobalanus'' (10); ''Liebmannia'' (3); ''Oerstedia'' (1); ''Pachybalanus'' (14); ''Pasania'' (209); ''Pseudosynaedrys'' (9); ''Synaedrys'' (15); indeterminate (12).
Early researchers into the family often suggested that the stone oaks were primitive in the family. An exhaustive study of the inflorescence and fruits of 73 species from eight of Camus' subgenera found that important development and evolutionary characters distinguish the major groups in the genus and indicate differences among the genera of the family.
]
Species
References
External links
* Individual species are described in detail o
www.asianfagaceae.com
*A full list of the species and their synonyms can be seen by entering ''Lithocarpus'' in the search box in th
World Checklist
Flora of China Online
includes descriptions of the 123 Chinese
Chinese can refer to:
* Something related to China
* Chinese people, people of Chinese nationality, citizenship, and/or ethnicity
**''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation
** List of ethnic groups in China, people of va ...
species
{{Taxonbar, from=Q132402
Fagales genera