The Pines constitute a large genus of evergreen trees divisible into three natural groups, viz. (1) those usually having two leaves in a sheath, such as the Corsican Pine (P. Laricio), and the Scots Fir (P. syl-vestris); (2) those with three leaves in a sheath, like P. Coulteri (macro-carpa) and P. ponderosa; and (3) those having five leaves in a sheath, like P. Cembra, P. excelsa, and P. Strobus, the Weymouth Pine.

Amongst the kinds most largely raised in nurseries are the Austrian Pine (nigricans or austriaca); P. Cembra, the Swiss Stone Pine, which grows almost anywhere. There are several forms, including a new golden one, aurea. P. excelsa, the Bhotan Pine, is a quick-growing Himalayan Pine with drooping blue-green tassels of flexible leaves. P. Jeffreyi grows up to 100 ft. high in California and flourishes in light soil. P. parviflora, 25-40 ft. high in Japan, is distinct in appearance. P. ponderosa attains a height of 300 ft. in California. The Scots Fir (P. sylvestris), 50-100 ft. high, is well known by its rugged reddish bark and dense heads of blue-green foliage; and the Weymouth Pine (P. Strobus), from North America, 80-170 ft. high in a wild state. The species mentioned are all valuable timber trees. There are several others not so largely grown.