12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



and described a great many more species than he should have done. 

 Some genera do not have a characteristic leaf form, but to make such 

 a statement of genera such as Liquidambar, Betula, Corylus, Ulmus, 

 Platanus, Sassafras, Liriodendron, Acer, Potamogeton, Cornus, and 

 Nymphaea, to mention but a few of those recorded from the Arctic 

 Tertiary, is the height of misunderstanding. Moreover, as I pointed 

 out in 1922 {op. cit., p. 4) : " Plant fossils have this merit aside from 

 any question of botanical identification, and this feature seems to have 

 been lost sight of by numerous critics of paleobotanical practise: 

 that the size and form of leaves, their texture, the arrangement and 

 character of their stomata, and the seasonal changes in wood, afford 

 criteria that are quite as valuable climatically even though the species 

 or genus to which they belong remains undetermined." Furthermore, 

 a great many of the generic determinations are corroborated by fruits 

 and seeds, as for example, the genera Vitis, Acer, Nyssa, Hicoria, 

 Juglans, Liriodendron, Fraxinus, etc. 



As recorded in the literature the number of species varies from 

 the single Pinus recorded from Bathurst Island, 5 species from Elles- 

 mere Land, 6 species from Banks Land to 55 species from Iceland, 

 168 species from Spitzbergen, and 283 species from Greenland, the 

 last being greatly overelaborated. I have shown ^ that Heer's 30 species 

 of fossil plants from Grinnell Land (Lat. 81° 42') represent not more 

 than half that number ; and that Viburnum, Alnus, Ulmus and Tilia 

 represent Populus and Corylus. As thus revised the Grinnell Flora 

 contains nothing extraordinary unless it be the supposed Nymphaea 

 rootstock and this may really belong to one of the plants represented 

 by fragments of grasses or sedges. 



I will consider only the four most extensive of these floras in any 

 detail. These are Iceland, Spitzbergen, Greenland and Alaska. 



The Icelandic flora is preserved in tuffs, along with fresh-water 

 diatoms, Unios, Potamogeton ; and the wood and branches appear 

 to have been broken off and buried by showers of ashes. The woods 

 show sharply marked seasonal rings; and conifers, willows, alders, 

 birch, and hazel are prominent. The only plants certainly determined 

 that might not justly be considered cool temperate are the following: 

 Platanus, Liriodendron, Acer, Juglans, Ginkgo, Fraxinus, Hicoria. 

 Representatives of all of these except Ginkgo, which is not a native, 

 and Liriodendron, which reaches its northern limit in southern New 

 England, are hardy in northern New England (Platanus) or eastern 

 Canada (Acer, Juglans, Hicoria, Fraxinus) at the present time. 



^ Berry, Edward W., Proc. Anier. Phil. Soc, Vol. 61, pp. 8-9, 1922. 



