Fig. 72.—Protophyllum boreale, Dawson, reduced. Upper Cretaceous, Canada.
The single species of the beautiful Liriodendron, or tulip-tree, is a remnant of a genus which had several Cretaceous species (Figs. [74], [75]). The magnolias, still well represented in the American flora, were equally plentiful in the Cretaceous ([Fig. 73]). The walnut family were well represented by species of Juglans (butternut) and Carya, or hickory. In all, no less than forty-eight genera are present belonging to at least twenty-five families, running through the whole range of the dicotyledonous exogens. This is a remarkable result, indicating a sudden profusion of forms of these plants of a very striking character. It is further to be observed that some of the genera have many species in the Cretaceous and dwindle toward the modern. In others the reverse is the case—they have expanded in modern times. In a number there seems to have been little change.
Fig. 73.—Magnolia magnifica, Dawson, reduced. Upper Cretaceous, Canada.
Dr. Newberry has given, in the “Bulletin of the Torrey Botanical Club” an interesting résumé of the history of the beautiful Liriodendron, or tulip-tree, which may be taken as an example of a genus which has gone down in importance in the course of its geological history.
"The genus Liriodendron, as all botanists know, is represented in the present flora by a single species, ‘the tulip-tree’ which is confined to eastern America, but grows over all the area lying between the Lakes and the Gulf, the Mississippi and the Atlantic. It is a magnificent tree, on the whole, the finest in our forests. Its cylindrical trunk, sometimes ten feet in diameter, carries it beyond all its associates in size, while the beauty of its glossy, lyre-shaped leaves and tulip-like flowers is only surpassed by the flowers and foliage of its first cousin, Magnolia grandiflora. That a plant so splendid should stand quite alone in the vegetation of the present day excited the wonder of the earlier botanists, but the sassafras, the sweet-gum, and the great Sequoias of the far West afford similar examples of isolation, and the latter are still more striking illustrations of solitary grandeur." (Figs. [74] and [75].)
Fig. 74.—Liriodendron Meekii, Heer. (After Lesquereux.)