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Oak TreeOak tree classificationThe term “oak” is found in the common name of several hundred tree and shrub species in the genus Quercus and several other related genera, such as Cyclobalanopsis and Lithocarpus. The genus Quercus is considered to be the main oak tree genus and contains roughly 500 species; all native to the Northern Hemisphere. In Indonesia, oak trees do however grow in the southern hemisphere as well.
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The large Quercus genus is divided into five sections. Hybrids are commonly occurring among wild oak trees, but crossings between two oak trees belonging to different sections are very rare. Hybridization will instead typically take place between different species belonging to the same section. A notable exception to this general rule is the sections named Quercus and Mesobalanus between which inter-sectional hybridization is quite common.
Oak tree section Quercus
This section contains the so called white oaks native to Asia, Europe and North America. Oak tree species belonging to this section will have short styles and produce acorns that are sweet or somewhat bitter. The acorns will need 6 months to mature and there are no hairs to be found inside the shells of the acorns. These oak tree species will develop leaves that tend to lack a bristle on the lobe tips. It is common for the lobe tips to be rounded.
Oak tree section Cerris
This section is where you will find the well known Turkey oak (Quercus cerris) and its less famous relatives. Oak tree species belonging to this section are native to Europe and Asia. They produce long styles and their acorns will need 18 months to mature. The inside of the acorn shells are without hair and the acorns have an extremely bitter taste. The leaves will typically display sharp-lobed tips with bristles.
Oak tree section Lobate
In this section you will find the so called Red Oaks that grow from North America down to the northern parts of the South American continent. Red oak species have long styles and produce extremely bitter acorns that will need 18 months to mature. The inside of the acorn shell is woolly. Red oak trees develop sharp-lobed leave tips with bristles.
Oak tree section Mesobalanus
The most well known oak tree species from the section Mesobalanus is the Hungarian oak (Quercus frainetto). The oak tree species in this section are native to Europe and Asia. They produce long styles and their acorns need no more than 6 months to mature. The acorns have a bitter taste and the inside of the acorn shell is not woolly. The Mesobalanus oak tree species are all closely related to the Quercus oak tree species, and some classifications even include the Mesobalanus oak tree species in the Quercus section.
Oak tree section Protobalanus
Oak tree species from this section are not found outside southwest United States and the north-western parts of Mexico. The most well known example of a Protobalanus oak tree species is probably the Canyon Live Oak (Quercus chrysolepis). Oak tree species in this section develop short styles and their acorns need 18 months to reach maturity. The acorns are extremely bitter and protected by a shell that is woolly on the inside. The leaves usually have sharp-lobed tips and you can see bristles at the tip of the lobe.
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Copyright 2005 oak-tree.info. Pictures based on a picture by wikipedia user MPF
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