From DT Online

Quercus robur

The Taxonomy of the plant Kingdom classifies trees as either Angiosperm (encased seeds) or Gymnosperm (naked seeds). These sub-divisions are each sub-divided into Genus (a subgroup of organisms that have many common characteristics such as oaks or pines) then Species which can be thought of as a specific kind of tree - but this too can be further sub-divided into Varieties for example.

An accurate way to name a tree is to give the Latin names for both its Genus and Species (e.g. Quercus robur is the name given to English Oak).

Hardwoods include Deciduous trees grown in Temperate Climates such as ours (many hardwoods in Tropical Climates are Evergreen). They have broad leaves and are fruit-bearing or have seeds borne enclosed in cases - and so are classified as Angiosperms.

Examples growing in the UK include: Oak, Ash, Elm, Sycamore, Walnut, Birch, and Beech plus any Fruitwood such as Apple, Pear or Cherry. Non-native examples include: Mahogany, Rosewood, Teak, Ebony, Obeche, Ramin, and Jelutong. Balsa is also a Hardwood even though it is very soft - the distinction between Hardwoods and Softwood is not determined by how hard or soft they are.