The conifers are a group of about 588 species of trees and shrubs that include many of the best-known plants in the world. All conifers bear seeds inside cones, woody protective structures. There are seven families of conifers. The largest is the Pine family (232 species), which includes such familiar trees as pine, spruce, fir, and larch. Most plants in this family have needlelike foliage and bear their seeds in a cone formed of papery or woody scales whorled about a central axis. The Pine family includes the oldest known trees, the bristlecone pines, many of which are known to be more than four thousand years old.