Any tree of the genus Pinus, of the family Pinaceae, characterized by evergreen leaves, usually in tight clusters (fascicles) of two to five, rarely single. There are about 80 known species of pine distributed throughout the Northern Hemisphere. Botanically, the leaves are of two kinds: (1) a scalelike form, the primary leaf, subtending a much shortened and eventually deciduous shoot, which bears (2) the secondary leaves or needles. The wood of pines is recognized easily by the numerous resin ducts and the characteristic resinous odor. The pines may be divided into two classes, according to the number of leaves in a cluster.