QUATERNARY PLANTS The latest chapters in the history of our planet belong to the Quaternary period, and to these chapters plants contribute a very important share. We confine our attention to the Quaternary of Europe, because from it comes almost the whole of our in formation. The most important feature so far disclosed in the Quaternary of America is the presence of a few east Asian or European plants—Xanthium, Pterocarya, cinnamon and laurel, which died out later.
Compared with the Tertiary, the Quaternary period was short —a few hundred thousand years. The important facts regarding it are : (I) In north Europe a series of rapid and marked climatic changes took place. (2) Throughout the period man is known to have lived.
With the Quaternary ice age, the cooling of the northern regions, which had been going on since the Eocene, reached a climax. The ice age was not a period of unbroken Arctic cold. This is shown clearly by beds of temperate plants intercalated between others showing cold conditions. Such temperate, inter glacial beds have been found throughout north Europe, includ ing Britain. Most of the plants now live in these regions; a few are extinct: and others survive elsewhere. The British plants indicate a climate about as warm as, but drier than, that of the present day.
In beds of preceding and succeeding age colder types of plants occur. Dwarf arctic willow and the arctic birch flourished on the plains of Germany and in the south of England. The ground was gay with arctic and alpine flowers—Primula farinosa, Saxi fraga oppositifolia, Dryas octopetala, Polygonum viviparum, the alpine poppy, flax, potentilla, geranium, scabious, campanula, gen tian and the bearberry. Ranunculus hyperboreus, one of the most arctic of buttercups, grew in the Isle of Wight. It now lives no further south than the Dovrefjeld mountains, Lapland, Alaska and Labrador. These changes were going on whilst palaeolithic man lived in Europe.
Subsequently the climate ameliorated. The snow and ice re treated, although slight alternations of climate still occurred. Some of these have been traced by the statistical study of pollen in peat. Using this study for the investigation of peat dredged from the floor of the Dogger Bank, 6o ft. beneath the sea, Dr. G. Erdtman, of Stockholm, discovered that it belonged to the "boreal" period, when the climate was cold but not arctic. The peat had previously been studied by the Reids who found evi dence of a great fenland stretching from England to the Con tinent. The "boreal" period which saw this fenland in existence belongs to the age of early Neolithic man. In Neolithic deposits various cultivated plants are found : wheat, barley, millet, apples, pears, the opium poppy and flax.
As prehistory passes into history we glean interesting scraps of information. Tutankhamun was buried with a string of seeds
from the magic mandrake around his neck ; the Celts grew wheat, barley and beans at Glastonbury; and the Romans brought coriander, fig, grape and mulberry to Silchester, also many vege tables and wild fruits.