BIOGRAPHICAL NOTES. 427 
4. That their distribution has been effected by natural causes; 
but that these are not necessarily the same to which they are now 
exposed. 
In the light of modern knowledge these may appear to be trivial 
generalizations, but when we remember that they were worked out 
from original observations, and that they preceded Darwin’s “Origin 
of Species” by seven years, they deserve to be considered as very 
remarkable. In fact, Darwin acknowledges in several places, his 
indebtedness to Hooker, both for facts and for ideas. 
The science of zoological and botanical Distribution of Species is 
usually considered to belong to the last decade or two, but we find 
Hooker at p. xxiii. of this same introduction, laying down his ideas 
on the subject very clearly. He points out that to extend a 
theoretical application of these views to the New Zealand Flora, it is 
necessary to assume that there existed at one time land communi- 
cation by which Chilian plants were interchanged, at the same or a 
later epoch the Australian, at a third the Antarctic, and at a fourth 
the Pacific forms. To effect this, no continuous connection was 
necessary, for an intermediate land, peopled with some or all the 
plants common to both, may have existed between New Zealand and 
Chili, when neither of these countries was as yet above water. He 
considers that to account for the Antarctic species which occur on 
our mountains, a new set of influences is demanded. And this new 
set of influences he considers to have been climatic; the antarctic 
plants having been its most ancient colonists, and under the changing 
circumstances, to have been compelled to retreat to the tops of the 
mountains. This idea is also supported by the fact that the plants of 
cosmopolitan range occurring in New Zealand and the Antarctic 
islands, are just those which have a great climatal range in other 
parts of the world, ¢.g., Montia fontana and Epilobium tetragonum. 
Later on, in the same essay, he says, that considered by the number 
of uni-sexual or polygamous flowered plants, as well as the large 
number of orders, with limited number of species represented, the 
New Zealand flora is much the most difficult on the globe for a 
beginner. 
In 1855, Hooker became Assistant-Director of the Kew Gardens, 
and succeeded to the Directorship on his father’s death, in 1865. 
These were busy years. He had opportunities to travel, whereby he 
was enabled to study the plants of the southern shores of Europe, 
South Africa, and America. 
The introductory essay to the “Flora Tasmaniex” is dated Nov. 
4, 1859, and this marks the completion of the publications of the 
Antarctic voyage. The time was auspicious, for on the previous day,. 
Mr. Alfred Russell Wallace had read at the meeting of the Linnean 
Society of London, his paper on the Geographical Distribution of 
Animals in the Malayan, New Guinea, and Australian continent and 
islands, and Mr. Darwin’s work on the “Origin of Species” had just 
appeared. In this essay, which deals generally with the origin of 
the Australian flora, the views first promulgated in the New Zealand 
flora are worked out in great fulness, and in the light of increased 
knowledge. The manifest relationship of the New Zealand to a large 
part of the Australian flora presents difficulties which we are only 
