Division: Coniferophyta

Class: Pinopsida
Pinales (Coniferales)
Cupressaceae (Cypress)
Taxaceae (Yews)
Pinaceae (Pines)

Division: Coniferophyta
    These are trees or shrubs which reproduce by seeds (matured ovules). They increase in diameter by a cambium layer which produces xylem (woody tissue which makes up most of a tree trunk, which conducts water from the roots to the leaves) toward the inside and phloem (commonly called the bark, which conducts food manufactured by the leaves to the roots) to the outside, and thus have true, well-developed secondary growth. Secondary growth is composed of any cells produced by cell divisions in the original growth which is referred to as primary growth.
Pollen is produced in separate small male cones from the larger female cones which produce ovules. Ovules are produced naked on the adaxial (toward the main axis) surface of cone scales. The Division Pinophyta has no ovaries. The Division Pinophyta differs from flowering plant division (Magnoliophyta) in that there is no container or ovary surrounding the ovules and thus produces no true fruit (fruits are matured ovaries). Pollination occurs by wind transfer of the pollen from pollen producing cones to the seed cones. The pollen lands on a droplet on the micropyle (micro=small; pyle=opening); opening of the female gametophyte). The female gametophyte is haploid, thus its nuclei contains only half as many chromosomes as the rest of the cells in the tree. It is multicellular and produces archegonia (The organ in which the female sex cells are produced). The seeds of the Pinophyta contain no endosperm as in the Magnoliophyta. The food reserves for the developing embryo are stored in the tissue of the female gametophyte. The sporophyte (2n generation) is the dominant and obvious, independent generation. The sporophyte has simple leaves which are usually needle-like and small. The vascular system of the leaves consists mainly of a midvein. The veins do not form an anastomosing (closed network) vascular system.

Class: Pinales (Coniferales)
     The conifers found in Idaho are monoecious (both sexes on one plant specimen) or dioecious (Pollen producing cones only on one plant and seed producing cones on different plants–e.g. Taxaceae) trees or shrubs (trees and shrubs are perennials because above ground parts remain alive year after year) with either scale-like or needle-like simple leaves. Most of ours are evergreen, but one species (the larch or tamarack) is deciduous. Reproduction structures are in cones (strobili) rather than flowers. Thus there is no calyx, no corolla, and no pistil. The several stamens are spirally arranged in small, deciduous strobili (fall off after pollen is shed). The stamens are on the abaxial (side away from the main cone axis) surface of the cone scales. Each stamen has two or more anther sacs. There is one ovule in the Taxaceae cones, but the rest have 2 to many which are produced in pairs on the adaxial surface of spirally arranged scales in woody cones e.g., hemlocks [Taxaceae], pines, spruces, firs, douglas firs [Pinaceae] or fleshy cones in the junipers, arborvitaes [Cupressaceae]. The matured ovules (seeds) tend to be large and contain abundant food reserves. Most species have two ovules or seeds born in pits near the base of each scale but a few have several. Several have winged seeds. The embryo has two to several cotyledons. Seeds are dispersed by shrinkage of the cones which allows seeds to fall out, by cones disintegrating, or by serotinous cones which are opened by animals, decay, or by fire.

Class: Taxales
     This class contains only one family, the Taxaceae. Thus the description of the class Taxopsida and family Taxaceae are the same. They are commonly dioecious (but can be monoecious) evergreen trees and shrubs which have no resin canals. The branches tend to spread or droop. The spirally arranged, linear, need-like leaves sometimes appear to be in two ranks. The pollen is produced in small cones whose scales bear 2-8 pollen sacs. The ovules is solitary in a small cone which has 2 pairs of bracts. At maturity, a red aril almost completely surrounds the black seed which can be seen from the distal end. The final result does not appear to be a cone, but appears to be a berry. Differing from the Pinaceae cleavage embryony does not occur in the Taxaceae. The fleshy, red aril is edible, but the black, shiny seed is poisonous to mammals, including Homo sapiens. The hard, durable, attractive wood has been and is still used for making bows.

Information by Dr. Karl E. Holte, ©2001.