ABSTRACT
Of the two classes of flowering plants the Gymnospermae are the more primitive and ancient. Nevertheless, they contain a group of plants which still dominate the vegetation over considerable portions of the land masses of middle and high latitudes, particularly in the northern hemisphere. The coniferous tree, with its tapering, symmetrical form and needle-shaped leaves can still compete successfully with the broad-leaved trees of the Angiospermae in quite a variety of environments. Species of pine (Pinus spp.), spruce (Picea spp.) and fir (Abies spp.) are particularly common and widespread. The vast majority of conifers are evergreen, (the deciduous larches (Larix spp.) being exceptional in this respect), and there can be little doubt that the evergreen habit, linked with other common characteristics of the conifers, account for their widespread dominance.
