Coniferophyta

views updated Jun 08 2018

Coniferophyta (Pinophyta) The biggest division of gymnosperms, with a long fossil history, comprising trees and shrubs, nearly all of which are evergreen, commonly with monopodial crowns. Most are resinous. The wood lacks vessels (see TRACHEA and VESSEL ELEMENT). Conifers are extremely important for timber and paper production. The leaves are often needle- or scale-like. Fertile parts occur in unisexual cones, variously containing sterile scales. Stamens are borne on commonly peltate scales. The ovule and seed are naked and borne on a scale. They first appear as fossils in Carboniferous rocks. There are about 550 extant species.

Coniferophyta

views updated May 21 2018

Coniferophyta A phylum of seed-bearing plants comprising the conifers, including the pines, firs, and spruces. Conifers have an extensive fossil record going back to the late Devonian. The gametes are carried in male and female cones, fertilization usually being achieved by wind-borne pollen. The ovules and the seeds into which they develop are borne unprotected (rather than enclosed in a carpel, as are those of the Anthophyta). Internal tissue and cell structure of these species is not as advanced as in the angiosperms. Conifers are typically evergreen trees inhabiting cool temperate regions and have leaves reduced to needles or scales. The wood of conifers, which is called softwood in contrast to the hardwood of angiosperm trees, is widely used for timber and pulp. See also gymnosperm.

Coniferophyta

views updated May 08 2018

Coniferophyta (Pinophyta) The biggest division of gymnosperms, with a long fossil history, comprising trees and shrubs; most are resinous. The leaves are often needle- or scale-like. Fertile parts occur in unisexual cones, variously containing sterile scales. The ovule and seed are naked and borne on a scale. They first appear as fossils in Carboniferous rocks.

Pinophyta

views updated Jun 11 2018

Pinophyta See CONIFEROPHYTA.