松树是松科（Pinaceae）植物的统称，尽管在汉语中，其中不少种类被称作“杉”，一般特点乃叶的形状像针，防止水分大量被蒸发。而在一些气候较不炎热，约北纬40多度至60度的地方（如欧洲等），这类型植物亦为常见。松科有11属约220-250种，主要分布在北半球。

扁平线形或针形的叶子，螺旋状互生，或在短枝上成簇生状；常雌雄同株；球花的雄蕊及具有胚珠的种鳞也均为螺旋状互生；雄球花的雄蕊具有2个药囊，雌球花的种鳞具有2个胚珠，种鳞背面的苞鳞和种鳞分离。

另外松树的针叶并不是直接长在枝条上，而是着生在枝叶交接处的节状叶枕上。每根松针的外围都有着一层厚的角质层和一层腊质外膜，这样减少了松树水份的丧失，也是松树可以在干燥环境下生存的原因之一。

The Pinaceae (pine family) are trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae are supported as monophyletic by their protein-type sieve cell plastids, pattern of proembryogeny, and lack of bioflavonoids. They are the largest extant conifer family in species diversity, with between 220 and 250 species (depending on taxonomic opinion) in 11 genera, and the second-largest (after Cupressaceae) in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family often forms the dominant component of boreal, coastal, and montane forests. One species, Pinus merkusii, grows just south of the equator in Southeast Asia. Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.