Conifer

Conifer, common name for a group of plants that is characterized by seed-bearing cones and that includes about 550 of the 700 known species of gymnosperms, plants with seeds that are not enclosed in an ovary. There are two orders of conifers. Conifers are known from fossils more than 290 million years old. Although more species of conifers once existed, they are still a widely distributed group and are one of the world's most important renewable resources. In late 1994, descendants of a group of conifers widespread in the Cretaceous period were discovered in the Wollemi National Park, near Sydney, Australia. Thirty-nine trees, the tallest of which reaches a height of 40 m (130 ft), were found in a remote area of the rain forest. Fossils of the ancestors of the newly discovered trees exist, but scientists had believed that the group had become extinct 50 million years ago.

Conifers, like flowering plants (see Angiosperm), reproduce by means of seeds, which contain food tissue and an embryo that will grow into a plant. The seeds are borne on the scales of female cones rather than being surrounded by carpel tissue, and the pollen is produced in separate male cones rather than in anthers. Pollination in conifers is always dependent on wind currents to blow the abundant yellow pollen from the male cones to the female cones. Conifers usually have needle-shaped or scalelike leaves, and nearly all are evergreen. They typically have straight trunks with horizontal branches varying more or less regularly in length from bottom to top, so that the trees are conical in outline. They vary in size from shrubs to giant sequoias. See Arborvitae; Cedar; Cypress; Douglas Fir; Fir; Hemlock; Juniper; Larch; Pine; Sequoia; Spruce; Yew.

Scientific classification: Conifers constitute the phylum Pinophyta. The two orders of conifers are Pinales and Taxales. The newly discovered Australian conifers belong to Auracariaceae, a family of primitive trees.