8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



LOWER CRETACEOUS 



Lower Cretaceous floras are found along the east coast of Asia, 

 in Alaska, Greenland, and King Charles Land. From the last a 

 number of coniferous woods have been described by Gothan. These 

 show pronounced growth rings, said to be more prominent than in 

 woods of the same age from central Europe. Nathorst records an 

 incomplete trunk 32 inches in diameter and showing 210 seasonal 

 rings. The most extensive Arctic flora of Lower Cretaceous age is 

 that described by Heer from the Kome beds of western Greenland, 

 but this, although generally considered to l)e of Barremian age, is 

 subject to doubt as to age and content l)ecause collectors appear to 

 have mixed several Cretaceous horizons. As it stands in the literature 

 it comprises over 100 species, including 46 ferns (no less than 15 

 are referred to Gleichenia, and although these surely represent that 

 genus they are artificially multiplied), i marsilea, i lycopod, 3 equise- 

 tums, 13 cycads, 20 conifers, 2 ginkgos, 5 monocotyledons, 3 or 

 4 dicotyledons, and 6 of uncertain identity. The abundance of ferns 

 indicates a humid climate as does the presence of coal. This flora 

 dififers very little from those of corresponding age in lower latitudes 

 ((?. g., the Kootenai of western Canada and Montana). 



UPPER CRETACEOUS 



Strictly Arctic Upper Cretaceous floras are limited to Alaska and 

 Greenland but others of this age are found in northern Europe and 

 eastern Asia. The most extensive is that from the two horizons in 

 West Greenland known as the Atane and Patoot beds. These have 

 in large part been described by Heer and there is a great and un- 

 warranted multiplication of species. That from the Atane beds has 

 184 recorded species. It includes 31 ferns, i equisetum, i selaginella, 

 I marsilea, 12 cycads, 2 ginkgos, 25 conifers, 4 monocotyledons, 94 

 dicotyledons and 14 of uncertain affinities. 



The seemingly most incompatible plant is the authentically deter- 

 mined Artocarpus and this raises a question which cannot be decided 

 without prejudice. If a genus which is tropical at the present time 

 is found fossil associated with a prepondcratingly temperate flora, 

 which is to be given the most weight? The one or the many, bearing 

 in mind the latitude where they occur? My own feeling is that the 

 majority are less likely to have altered their environmental require- 

 ments than the minority, but this falls short of actual proof. 



The Patoot flora includes 19 ferns, i equisetum. 19 conifers, 2 

 monocotyledons, 80 dicotyledons, and 2 uncertain. 



