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Geographical Distribution of Indigenous Plants. 55 
direct line across the South Pole ; and with even a moderate amount 
of land intervening, it would not be very difficult for plants to find 
their way from one country to another, The similarity between the 
floras is abundantly illustrated by a table of fifty-five species of plants 
of temperate and cold South America, which represent the same num- 
ber of species in New Zealand and Australia. There are really 89 
species, or nearly one eighth of the flora of New Zealand, which are 
also South American.* | 
The same explanation of the glacial epoch would account for the 
finding on the mountain of Kini-Balu, in Borneo, at 8,000 feet elevation, 
of three very peculiar Antarctic, Tasmanian and New Zealand genera, 
viz.: Drapetes, Phyilocladus, and Drimys, “which are almost unknown | 
in the northern hemisphere.” 
Having now shown that the long periods of time necessary for the 
wide distribution of plants are granted by the antiquity of the Ameri- 
can continent, and explained the importance of the glacial epoch to the 
theory, I shall now proceed to show the similarity existing between 
the floras of Europe and the northeastern United States, and show 
reasons for expecting this similarity. It has existed for a long time. 
In the Cretaceous rocks of Kansas and Nebraska, are found many 
plants of existing genera. The species of these genera are, many of 
them, closely allied to those now livingin America. When we turn to 
Europe, and compare our fossils with those of the Cretaceous forma- 
tions there, many of the species are found to be identical in both for- 
mations.{ Not only this, but we find in the Cretaceous rocks of Green- 
land, in 70 deg, N. latitude, the same fossil forms that formerly lived 
* Hooker Intro. Flor. New Zealand, pp. xxx-xxxvi. While on this subject, it might be well 
to state that Dr. Hooker found it difficult to account for the fact that though many typi- 
cal genera and species of New Zealand were found in Australia, only a few peculiar genera 
and species of Australia were found in New Zealand, though they were well adapted for 
transportation by ocean currents. The difficulty is partly solved when we find that the 
ocean currents run from New Zealand toward Australia, instead of in the reverse direction. 
Seeds could then only be transported from the former to the latter. Mr. Wallace, in his new 
book, on ‘‘ Island Life,’’ suggests another explanation. He supposes Australia to have been 
divided during the Cretaceous period into two islands, the Temperate on the west, and the 
Tropical on the east. -The eastern island was united to New Zealand by a spur of land, 
which allowed an interchange of fauna and flora, while the west island never was united 
to New Zealand. Finally, the channel which separated the east and westislands of Austra- 
lia was closed, and New Zealand and East Australia. were separated. If this explanation is 
the true one, then the greatest similarity should exist between East Australia and New 
Zealand; and the greatest difference be found between New Zealand and West Australia. 
This has been found to be the case, and the data can be found in Dr. Hooker’s essay, ‘** on 
the Flora of Australia,’’ 1859, pp. l-liv. 
+ Hooker, Flora New Zealand, p. xxxvi. 
t See Lesquereux, Cretaceous Flora of the W. U.S. In U.S. Geo. and Geog. Sur. of 
Terr., W.ash., D.C., 1874, vol. vi. 
