CAMPBELL: THE ORIGIN OF THE HAWAIIAN FLORA 93 
Malaysian genera are much more numerous than the American. 
There are forty-five genera of Phanerogams belonging to the 
former regions which are entirely absent from the New World; 
while only eight genera are exclusively Hawaiian-American. One 
genus, Gynandropsis (Capparidaceae) belongs to South America 
and South Africa, while three endemic Hawaiian genera of Com- 
posite—viz., Argyroxiphium, Wilkesia, and Raillardia are closely 
related to certain Californian types. 
The Pteridophytes emphasize even more strongly the intimate 
relation between the floras of the Australasian and Malaysian 
regions and Hawaii. No less than thirty-eight species, absent 
from America, are common to the two areas, while only two 
species are confined to Hawaii and the American continent. 
While it is not unlikely that certain species of Phanerogams 
common to Hawaii and the southern Polynesian region may 
have been introduced in recent times, in most cases the Ha- 
Waiian species are distinct and peculiar to the Islands. The 
cocoanut, taro (Colocasia), sugar-cane, bread-fruit, and some 
other cultivated plants were undoubtedly introduced by man, and 
it is not unlikely that such useful trees as the kukui (Aleurites 
moluccana) and the mountain apple (Eugenia malaccensis) were 
also introduced, although now they form almost the entire forest 
of the lower elevations. 
The American-Hawaiian genera are mostly found in the An- 
dean region and as there is considerable evidence of a former con- 
nection of South America with the Australasian region, it is pos- 
sible that some of these forms may have reached Hawaii from the 
south and have survived in the two extremes of their range, dis- 
appearing in the intermediate regions. 
While it is extremely probable that some species reached the 
Islands since their complete isolation, either by means of ocean 
currents, wind, or the agency of migratory birds, this, as condi- 
tions are at present, could have taken place only under very excep- 
tional circumstances. It is difficult to see how any of these 
agencies would account for the introduction of many plants of the 
cool rain-forest, which could hardly survive any such means of 
transportation. 
As to the line of connection between Hawaii and some former 
