THE VASCULAR FLORA OF MACQUARIE ISLAND.—CHEESEMAN. 
49 
of France. In Norway, beyond the Arctic circle, pine forests and cultivated farms 
exist. Spitsbergen, which extends as far north as lat. 80°, possesses 120 vascular 
plants, and botanists estimate that not less than 400 species are found within the 
arctic circle. Why should there be this extraordinary difference between the northern 
and southern floras ? 
No doubt the explanation is mainly climatic. But the winter temperatures 
of the subantarctic zone are certainly not excessive, and in most localities are milder 
than those obtaining in similar latitudes in the northern hemisphere. Professor 
Rudmose Brown (Problems of Antarctic Plant Life, p. 5) is probably right in 
concluding that the short and inadequate summer, with its comparatively low 
temperatures, is the most powerful reason. It does not provide a sufficiently long 
season of growth to enable most plants to reach their flowering stage, or to mature 
their fruit. In Macquarie Island the mean temperature of the three summer months 
is as low as 43-9°, and only exceeds the mean of the three winter months by 5-3°. But 
I have already pointed out that the small yearly range of temperature is one of the 
peculiarities of the climate of the subantarctic zone. The almost continuous westerly 
gales must also exercise an adverse influence on plant-growth, especially on Macquarie 
Island, where the statistics obtained by the Mawson Expedition have proved that the 
force of the wind considerably exceeds that recorded in South Georgia and Kerguelen. 
Professor Rudmose Brown has also drawn attention to another factor inimical to 
vegetation in “ the myriads of penguins which occupy almost every bare spot of 
ground during the nesting and breeding season,” and which must have a great effect 
in preventing the establishment of vegetation, or in destroying it when established. 
But although the reasons given above must have a powerful effect, they do not seem 
to be altogether sufficient, and I must agree with Dr. Skottsberg in considering the 
paucity of phanerogams in South Georgia (to which I would add Kerguelen and 
Macquarie Island) as altogether inexplicable. 
A little less than 400 miles north-east of Macquarie Island lies Auckland Island, 
the chief of the New Zealand outlying islands. Campbell Island, the next in size, is a 
trifle more remote, and more to the east. Antipodes Island is situated about 400 
miles east-north-east of Campbell Island, while the Snares, the only other island that 
supports a phanerogamic vegetation, is not far from half-way between Stewart Island 
and Auckland Island As the physical features, climate and vegetation have all been 
fully described in my recent memoir on the Subantarctic Islands of New Zealand, I 
propose to give a very brief account here. 
The first point to emphasise is that instead of rising from an ocean with an 
average depth of more than 2,000 fathoms, which is the case with the South Georgia— 
Kerguelen—Macquarie Islands, the New Zealand Subantarctic Islands stand upon a 
shallow plateau extending without a break to Stewart Island and far to the eastward 
of the South Island of New Zealand. In a straight line between Stewart Island and 
Auckland Island the depth is nowhere more than 400 fathoms, and in some places 
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