Page:Evolution of Life (Henry Cadwalader Chapman, 1873).djvu/139

Rh from the ovule, so far as known, is the same as that of the Coniferae, we turn now to that order.

The Coniferae, or cone-bearing trees, are so called from their fruit being in the form of cones, as in the Pines; "these cones are made up of flat scales regularly overlapping each other, and pressed together in the form of a spike or head; each scale bears one or two naked seeds in its inner face." "The pollen is contained in the substance of a body that retains in some degree its leafy type, and an assemblage of such bodies forms the 'catkin.'" In the Cypress we have cells (corresponding to stamens) at the edge of the leaf The leaves of Selaginella (a Cycopod), with their large and small spores (Figs. 136, 137), are as much flowers as the leaves of Coniferae with their organs. The Coniferae are invaluable to man, as including the most important of the timber-trees of cold countries, and furnishing the turpentines, resins, pitch, tar, and Canada Balsam. Among the Coniferae are found the Pines, Fir, Spruce, Cypress, Cedars, Larch, and Juniper. At certain seasons the ovule of Coniferae develops in its interior a mass of cells, the Endosperm; later in this Endosperm appear Corpuscles; within the Corpuscle is developed the Embryonic vesicle. The Ovule, Endosperm, Corpuscle, and Embryonic vesicle are to the Coniferae and Cycadae what the Large Spore, Prothallus, Archegonium, and Embryo-cell are to the Lycopods, the pollen of the Gymnospermae corresponding to the small spores of the Lycopodiaceae: the reproductive organs of Lycopodiaceae and Gymnospermae are, therefore, essentially the same. The higher plants differ from these orders in that the embryo-sac contains the embryo-cell only; whereas, in Lycopodiaceae and Gymnospermae, a Prothallus or Endosperm with Archegonia or Corpuscles is produced,