FOSSIL FLORA OF THE SECONDARY OR MESOZOIC PERIOD.
[Sidenote: Fig. 57. _Pinus sylvestris_, Scotch Fir.
Fig. 58. _Abies excelsa_, common Spruce Fir of northern Europe.
Fig. 59. _Larix Europæa_, the Larch, indigenous on the Alps of middle Europe.
Fig. 60. _Cedrus Libani_, Cedar of Lebanon.]
The Gymnospermous plants of the present day are included in two natural orders, Coniferæ and Cycadaceæ. Under Coniferæ are enumerated the various species of Pine (Fig. 57), Spruce (Fig. 58), Larch (Fig. 59), Cedar (Fig. 60), Eutassa, Araucaria (Fig. 61), Sequoia, Cryptomeria, Taxodium, Cypress, Juniper (Fig. 70), Salisburia, Dacrydium, Yew (Fig. 71), etc.
[Sidenote: Fig. 61. _Araucaria excelsa_, called also _Altingia_ or _Eutassa_ or _Eutacta excelsa_, Norfolk Island Pine.
Fig. 62. Woody tubes of fir, with single rows of discs.
Fig. 63. Woody tubes of fir, with double rows of discs, which are opposite to each other.
Fig. 64. Woody tubes of _Araucaria excelsa_, with double and triple rows of discs, which are alternate.
Fig. 65. Longitudinal section of the stem of a Gymnosperm, showing tubes of wood marked with punctations in one or more rows, and a medullary ray composed of cells running across the pleurenchyma.]
[Sidenote: Fig. 66. Linear leaves of _Pinus Strobus_, Weymouth Pine, in a cluster of five, with scaly sheath at the base.
Fig. 67. Cone of _Pinus sylvestris_, Scotch Fir.
Fig. 68. Cone of _Cupressus sempervirens_, common Cypress.
Fig. 69. Scale, _s_, of mature cone of _Pinus sylvestris_, with two naked winged seeds, _m m_, at its base; _ch_ marks the chalaza, _m_ the micropyle.]
The Coniferæ of the present day are distinguished as resinous trees or shrubs with punctated woody tissue (Figs. 62, 63, 64, 65), linear acerose or lanceolate parallel-veined leaves, sometimes clustered, and having a membranous sheath at the base (Fig. 66). Male flowers in deciduous catkins; female flowers in cones (Figs. 67, 68). The seeds are considered by most botanists as being naked, _i.e._ not contained in a true pistil (Fig. 69). Some of the conifers have a succulent cone, as the juniper (Fig. 70), and the yew (Figs. 71-73) has a succulent mass covering a single naked seed (Fig. 73). The yew also has its pleurenchyma marked both with punctations and spiral fibres. The arrangement of the punctations in the Coniferæ gives characters which enable us to classify the woods into groups that have some relation to the genera established from the reproductive organs (see Figs. 62-65).