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PACIFIC EXPLORATION: D.H.CAMPBELL 
SOME PROBLEMS OF THE PACIFIC FLORAS 
By Douglas H. Campbell 
DEPARTMENT OF BOTANY. LELAND STANFORD UNIVERSITY 
Read before the Academy. April 17, 1916. Received, July 6. 1916 
No botanist, who is at all acquainted with the rich and varied floras 
of the different regions of the great Pacific area, can fail to be impressed 
with the numerous important problems that present themselves — many 
of which have as yet received but scant attention. Perhaps most im- 
portant of all are those dealing with the origin and distribution of these 
rich floras. 
First, and perhaps foremost, is the collecting of data for a study of 
the relationships existing between the floras of the great Continental 
areas of the Southern Hemisphere, viz.: Australasia, South America, 
and South Africa. These areas, so completely separate at present, 
nevertheless show such similarities as to suggest a common origin for 
many of their elements. Such a study involves a consideration of the 
existing floras, which are pretty well known, but also an investigation 
of the fossil floras, in regard to which we are by no means so well in- 
formed as might be wished. Perhaps the fossils collepted in the recent 
Antarctic Expeditions may help us, and, of course, the investigations 
of the geologists in regard to possible former land connections must be 
taken into account. 
Second, a study of the floras of the innumerable islands of the Pacific 
should afford much material for many important generalizations. While 
our knowledge of the special floras — e.g., of the Galapagos Islands and 
Hawaii, is reasonably complete, there remains room for work concern- 
ing the origin of these floras and their later evolution. 
The Hawaiian Islands, especially, offer what is probably the most 
favorable field in the world for the study of the evolution of plant forms. 
Hillebrand, in his excellent Flora oj the Hawaiian Islands gives in the 
introduction (unfortunately left uncompleted by his untimely death), 
some most valuable suggestions of the possibilities afforded by a study 
of the flora of Hawaii. It is possible that further work has been done 
in regard to this matter since Hillebrand's, but if so, I am not acquainted 
with it. It is generally believed that these islands have always been 
thus isolated, and while this is not universally admitted, at any rate 
any former land connections must have been of a very remote period. 
A most striking feature of Hawaii is the different ages of the islands 
which have been formed in succession, beginning with Kauai at the 
