Cretaceous and Tertiary Plants of the Arctic Regions

CRETACEOUS AND TERTIARY PLANTS OF THE ARCTIC REGIONS Our knowledge of Arctic plants comes, in the first instance, from the studies made by Heer between 1868 and 1883. He rec ognized two periods for flowering plants. The older is referred to the Cretaceous. The newer, by him called Miocene, is now generally referred to the Eocene. He described about 335 species from the Cretaceous, and 282 from the Tertiary, but the num bers are certainly far too large, as indicated by Prof. A. C. Seward's work in 1926. The plants come from various localities within the Arctic Circle ranging as far north as Grinnell Land, lat. 81, and Spitzbergen, lat. 79. That the plants are in situ is shown by the fact that some are rooted.

Cretaceous.

In the lower beds of the Greenland Cretaceous, from Kome, occurs one of the earliest known flowering plants, called by Heer a poplar. From later beds at Atane, besides ferns, some of which are referred to genera now tropical, come many conifers such as Araucaria, Cupressus, Sciadopitys and Sequoia, palms, Artocarpus, Liriodendron, Magnolia, Sapindus, Sassafras, Rhus; species referred to Proteaceae and Menispermaceae ; also species of oak, poplar and fig. Still higher beds at Patoot contain

Acer, Acerates, Aralia, Zizyphus, also species of fig, walnut, plane and buckthorn, among flowering plants; and Dammara among conifers.

Eocene.

The late Prof. Nathorst stated that the Eocene beds of Spitzbergen yield Taxodium, Sequoia, Libocedrus, grass, sedges, pines, willows and pond-weed. From Cape Lyell he recorded Sequoia, Grewia, Magnolia, water-plantain, maple, poplar, willow, alder, birch, hornbeam, hazel, beech, oak, elm, plane and lime.

From Greenland Heer recorded Gingko, Libocedrus, Glypto strobus, Taxodium, Sequoia, Pinus among conifers ; Sassafras, Acerates, Nyssa, Vitis, Acer, Koelreuteria, Juglans, Rhus, and many catkin-bearing trees among flowering plants. The climate was temperate.

Most of these genera reappeared in the Tertiary of Europe and America. They are related to plants now living in Asia and America. Some also live in Europe. The occurrence of these plants within the Arctic Circle has a most important bearing upon the interpretation of plant-history in the Northern Hemi sphere.