Lithocarpus

Lithocarpus
Lithocarpus edulis, Kantō region, Japan
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Fagaceae
Genus:	Lithocarpus Blume
Species
See text.
Diversity
c. 330 species
Synonyms
Pasania Oerst.

See text.

Pasania Oerst.

Lithocarpus is a genus in the beech family Fagaceae, differing from Quercus in the erect spikes of insect-pollinated male flowers and the short styles with punctate stigmas on the female flowers. The World Checklist (see link below) accepts 334 species, though some other texts suggest as few as 100 species. About 100 Asian species of the genus were formerly treated in the genus Pasania. All are native to east and southeast Asia. These Asian species do not have a well-known English vernacular name, though the generic term stone oak has been proposed.

Until recently a North American species, the tanoak or tanbark oak was included in the Lithocarpus genus (Lithocarpus densiflorus), but recent genetic evidence suggests that the North American species is only distantly related to Asian species, and Tanbark-oak has been moved into a new genus, Notholithocarpus, based on multiple lines of evidence.

Lithocarpus trees are evergreen trees with leathery, alternate leaves, which may be either entire or toothed. The seed is a nut very similar to an oak acorn, but with a very hard, woody nut shell (hence the genus name, from Greek lithos, stone, + carpos, seed). The nut kernel is edible in some species (e.g. Lithocarpus edulis), but inedible, and very bitter, in others. A few sections of the genus have evolved a novel type of fruit where the seed is embedded in the receptacle material of the fruit which becomes highly lignified and hard, lending greater mechanical protection to the seed.

Several of the species are very attractive ornamental trees, used in parks and large gardens in warm temperate and subtropical areas.

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Wikipedia