Antiquity of the Angiosperms — SUESSENGUTH 
ily Ebenaceae, according to Fernald {in 
Vester, 1940: 174), and in the tribe Cyca- 
deae and the genera Po do carpus and Arau- 
caria, according to Studt (1926). 
It is doubtful whether any instances can 
be found to prove a considerable migration 
of a plant flora in the opposite direction, that 
is, from south to north. It is true, of course, 
that a number of plants, reported by Suessen- 
guth (1942), have worked their way north- 
ward from the South American Andes, reach- 
ing as far north as Costa Rica and Mexico. 
However, these migrations have taken place 
only since the Miocene elevation of the Cor- 
dilleras in Central America, and they are 
rather insignificant compared with the major 
southward migrations. 
There is evidence, however, that north- 
eastern Africa has been reached from a north- 
eastern direction by species of plants from 
India and western Asia. 
Although it might be expected that the 
Mediterranean floral elements might have 
arrived in central Europe from the south, fol- 
lowing the retreating glaciers as they with- 
drew to the north, I do not think this argu- 
ment is tenable, inasmuch as it is quite possi- 
ble that representatives of the Mediterranean 
flora might have found refuges in the climat- 
ically favorable parts of central Europe dur- 
ing the glacial advances. It is much more 
likely that the North American plants of 
Cenozoic time were forced southward by the 
glaciers, and then, after the glaciers had re- 
treated, were permitted to return north, to 
recover vast territories of their former areas 
of distribution. Nonetheless, these instances 
of northward migration are abundantly sur- 
passed by the notable removal to the south 
of plants in Australia, the Andes, Patagonia, 
Cape Colony, and the Balkans, in all of which 
real displacements to the south have been 
demonstrated. During the cold periods of the 
glacial advances, all of the hydro-megatherms 
and megatherms should have been concen- 
trated towards the tropics from the Arctic 
305 
and Antarctic regions, and it is not to be 
denied that a large part of the "small belt- 
like areas” of many families in the whole 
tropic range may thus have been established 
in their present ranges (Vester, 1940: 166 
et seq., figs. 93-113). Nevertheless, it seems 
as if in Australia, the Andes, Africa, and 
Europe other factors had contributed to force 
a great number of species of plants from the 
north to the south, and in those areas in the 
southern hemisphere this displacement car- 
ried the plants even farther south than the 
Tropic of Capricorn. 
This phenomenon of displacement from 
north to south does not need the supposition 
of some mystical power to explain it. In 
Africa, for example, a northward counter- 
displacement of the ancient flora of the north- 
ern and middle part of the continent could 
not happen because it was blocked in that 
direction by the broad Tethys sea of the early 
Tertiary period (Eocene time, and so on) or 
by the deserts that are its relics. Australia, 
to give another example, in post-Tertiary 
time could not receive plants from any direc- 
tion but from the north, because it was 
only there that Australia was connected, if 
only temporarily, by land bridges with large 
masses of land, while in the south the Ant- 
arctic continent at a later period was too cold 
and too far distant to permit of plant migra- 
tion. In the Andes plant distribution is not 
as easily explained. In the Balkans the lower- 
ing of temperatures in the north by the 
glaciers may have played a part in the south- 
ward displacement of the plant life, so that 
numerous types of plants died out in the 
north which continued to live in the south. 
It would be of great interest to investigate 
the degree of displacement in still other parts 
of the world. 
Many other objections might be raised to 
dispute this claim of the southward displace- 
ment of plants. The major point of dispute 
is whether or not this southward displace- 
ment of certain systematic groups — such as, 
