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32 The Philippine Journal of Science 1914 
destructive insects due to disturbances of the balance of nature, 
and various other factors. 
It is considered most probable that the islands of the whole 
Polynesian region, before the advent of man, like the Philippines, 
Guam, and the Hawaiian Islands, were entirely covered with 
forests, and that as a corollary none of the weeds and weed-like 
plants, now so abundant, were originally found in the region. 
If this assumption, as to the original vegetation of the group, 
be true, then Polynesia would be just as much a virgin territory 
to Asiatic weeds as to those of America. Any weed, adapted 
to the climatic conditions, once introduced, would thrive and 
multiply rapidly due to the fact that the open areas, occupied 
by but few species, had been prepared by man. 
Guppy‘ points out that the Polynesian weeds arrange them- 
selves into two groups, the “aboriginal” weeds, comprising those 
that existed in the islands at the time of Captain Cook’s expe- 
ditions in the latter half of the eighteenth century, and the 
“white man’s” weeds that have since been introduced. He states 
regarding the 64 weeds enumerated by Seemann that at least 
37 of them were found in the islands of the Pacific when the 
botanists of Cook’s voyages, Banks, Solander, the Forsters, and 
Nelson, made their collections (1768-79). Guppy" gives a list 
of the 37 species collected by the above botanists under the head 
of aboriginal weeds of which but 23 are now of rather universal 
distribution in the tropics of both hemispheres. The remainder 
are for the most part confined to, or at least natives of, the 
tropics of the Old World. Analyzing more in detail the 23 
“aboriginal” weeds, now of pantropic distribution, according to 
my present knowledge of weeds, their origin, and distribution, 
I conclude that but 5 are manifestly of American origin, that 
9 are equally definitely of Asiatic origin, and that 9 are doubtful 
as to origin but probably Asiatic. More in detail, I believe that 
. Teucrium inflatum Willd., Ageratum conyzoides L., Ipomoea bona- 
nox Boj., Waltheria americana L., and Physalis angulata L. are 
of undoubted American origin; Cassia sophera L., (?) Cardios- 
permum halicacabum L., Abrus precatorius L., Hydrocotyle asia- 
tica L., Siegesbeckia orientalis L., Vandellia crustacea Benth., 
Achyranthes aspera L., Eleusine indica Gaertn., and Adeno- 
stemma viscosum Forst., to be in all probability of Asiatic origin; 
and in my list of species that are doubtful as to origin, but 
probably Asiatic, I place Sida rhombifolia L., Geophila reniformis 
* Observations of a Naturalist in the Pacific 2 (1906) 415. 
*L. c. 604. 
