198 MERRILL. 
their possessions in tropical Asia and Malaya, and later the 
Dutch continued the work, so that it is now quite impossible, 
in many cases, to determine by whom the various economic 
plants and many weeds were first brought to the East; doubt- 
less many were distributed by representatives of all three na- 
tionalities. The Spaniards and the Portuguese were, however, 
unquestionably the pioneers in this respect, and the interchange 
of species between the tropics of the two hemispheres initiated 
by these pioneer explorers and colonists still continues. 
The American element in the Philippine flora is of peculiar 
interest as showing the effect of commerce on the vegetation 
of a country. Even with the limited communication between 
the Philippines and Mexico, it is surprising to consider the num- 
ber of American forms introduced here through the medium 
of the galleons in the years when all communication between 
Spain and the Philippines was via Mexico. From the time of 
the Spanish conquest up to the year 1815, a period of nearly 
300 years, the government galleons sailed annually for Manila, 
first from Navidad and later from Acapulco, on the western 
coast of Mexico. These galleons carried not only the civil, 
military, and ecclesiastical authorities between Spain and the 
Philippines via Mexico, but also other travellers, merchants, 
etc., as well as large quantities of merchandise. 
At an early date various Spanish officials, but, apparently, 
chiefly the priests, introduced here the various species of eco- 
nomic value, food plants, medicinal plants, fruits, etc., that were 
familiar to their countrymen in tropical America, most often 
bringing seeds, but in some cases most certainly living plants. 
Undoubtedly many species were introduced at that time that 
failed to become established here. Among the American species 
purposely introduced from Mexico may be mentioned the follow- 
ing: Maize (Zea mays L.), introduced for food; the pineapple 
{Ananas sativus Schultes), for its edible fruit and its fiber; 
maguey (Agave canUila Roxb.), for its fiber; the tuberose (Fo- 
lianthes tuberosa L.), for its fragrant flowers; the spider lily 
{Hymenocallis tenuiflora Herb.), for ornamental purposes; the 
canna (Canna indica L.), for ornamental purposes; arrowroot 
(Maranta arundinacea L.), for food; "aposotis" (Chenopodiiim 
ambrosioides L.), for medical purposes; four o'clock {Mirabilis 
jalapa L,), for ornamental purposes; "libato" (Anredera scan- 
dens Moq.) ; various species of Anona (A, muricata L., A. reti- 
culata L., and A. squamosa L.), for their edible fruits; the avo- 
cado {Persea americana Mill.), for its edible fruit; the Mexican 
