. The anatomy of woody plants. Botany -- Anatomy. CONIFERALES 355 present time. The accompanying genealogical tree (Fig. 254) will make clear the views as to sequence and affinities developed in the previous paragraphs of the present chapter. The Cordaitales of the Paleozoic serve as the starting-point, and from them were derived two cognate stocks—the Coniferales and the Ginkgoales. The latter have suffered much extinction and end in the present epoch in the sole surviving genus, Ginkgo. The Abietineae in earlier Mesozoic time gave rise to the Araucariineae, which flourished greatly in the la
. The anatomy of woody plants. Botany -- Anatomy. CONIFERALES 355 present time. The accompanying genealogical tree (Fig. 254) will make clear the views as to sequence and affinities developed in the previous paragraphs of the present chapter. The Cordaitales of the Paleozoic serve as the starting-point, and from them were derived two cognate stocks—the Coniferales and the Ginkgoales. The latter have suffered much extinction and end in the present epoch in the sole surviving genus, Ginkgo. The Abietineae in earlier Mesozoic time gave rise to the Araucariineae, which flourished greatly in the later epochs of that period, to become almost extinct in the glaciation which ushered in the Ter- tiary. The arauca- rian conifers dis- tinctly took their origin from the abietineous stock after it had developed. Corda/fa/es FIG. 254.—Genealogical tree of the Coniferales, showing their proximity to the Ginkgoales. ligneous resin canals, but before marginal ray-tracheids had made their appearance. The Podocarpineae-Taxineae may have originated at a still earlier epoch and before the abietineous stock had developed the resin canals or the marginal ray-tracheids which distinguish it from the Cretaceous onward. Unlike the Arau- cariineae the Podocarps and their allies, the yews, did not lose the opposite pitting and bars of Sanio common to the parent stock of both Abietineae and Ginkgoales. The Taxodineae are a still later offshoot of the strong abietineous line and come into existence sub- sequent to the appearance of marginal ray-tracheids and ligneous resin canals. Certain conifers of the earlier and later Mesozoic, such as Voltzia, Brachyphyllum, Geinitzia (sometimes erroneously desig- nated Sequoia}, etc., which have been referred to taxodineous. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Jeffrey, Ed
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