The spruce is in our part of the world the commonest of the great series of cone-bearing trees which we speak of as pines and firs. Botanists call this series or "natural order" of trees the Coniferæ, in reference to the fact that their flowers are cone-shaped growths consisting of scales set in a spiral order around a central stem. Each scale is more or less overlaid by a second small scale or "bract" (sometimes evanescent), and on the inner surface of the deeper scale the naked ovules are carried in the female cones, whilst the pollen-producing growths are similarly carried by the smaller and more delicate male cones. The ovules are exposed nakedly, and are, therefore, in a more primitive condition than those of ordinary flowering plants, in which they are overgrown and enclosed by the modified leaves which form the "pistil" or central part of the flower. Hence the conifers are called flowering plants with "naked seeds," or Gymnosperms, whilst the rest of the flower-bearing plants are called plants with "covered seeds," or Angiosperms. The cones are at first green (sometimes purple), and become brown as they ripen. The small loosely-packed male cones, less familiar to most people than the solid and large seed-bearing cones, are often of a fine crimson colour when young, and when ripe of a bright chestnut brown, but the cones of pine trees are with few exceptions (the Douglas fir is one) not brilliantly coloured nor set out to attract the eye, as are the flowers of most flowering plants. Though a young branch carrying its groups of green "needles," rich brown male cones, silver-white hairs and swelling seed-cones (Fig. 31) presents a very fine harmony of diverse colours, yet they are not constructed so as to attract the visits of insects. They do not require the services of insects to carry the pollen of the male cones to the ovules of the female cones. They produce an enormous amount of pollen, which falls in showers of yellowish-white dust, and is blown by the wind, far and wide, on to the female cones. Hence it is that though the cones are "flowers," and the pine trees are flowering plants, yet they have none of the beautiful shapes and colours which we associate, as a rule, with flowers--shapes and colours due to the modification in the latter of the leaves called "petals" which are set with attractive brilliancy around the stamens and pistil. The conifers are an ancient race, dating from geological ages before the chalk, when plants had not "learnt" (as they subsequently did) to colour their flowers and to provide nectar so as to ensure the visits of insects and the carriage by them of their pollen from plant to plant. Even in the group of plants with coloured flowers there are trees which have abandoned the production of colour in their flowers, and like the conifers depend upon the wind to carry their pollen instead of seeking the aid of insects.