\ 
192 MERRILL. 
DC, Desmodium trifiorum DC, Crotalaria verrucosa L., Teram- 
mis Utbialis Spr., Oxalis repens Thunb., Biophytum sensitivitm 
DC, Euphorbia hirta L., E. thymifolia Burm., E, hypericifolia L., 
Phyllanthus niruri L., P. iirinaria L., Sida cordifolia L., S. ac?*ia 
Burm., S. rhombifoUa L., S. retusa L,, Melochia cor cliori folia 
L., Centella asiatica Urb., Evolvulus alsinoides L., Solarium 
niginim L., Emilia sonchifolia DC, Eclipta alba Hassk., and 
Bidens pilosa L. 
In most treatments of tropical floras, whether of the eastern 
or of the western hemisphere, such species as the above are 
usually listed and discussed as native ones. It is far more prob- 
able that some have originated in one hemisphere and some in 
another, and that, for the most part at least, they have been 
accidentally distributed by man within the past 400 years. Cer- 
tainly many of them were widely disseminated at an early date 
in colonial history, and in most cases it is probable that their 
original homes will never definitely be known. 
Purposely introduced species comprise those of various other 
tropical countries that, for reason of their economic impor- 
tance, have been introduced either in prehistoric or within his- 
toric times. Naturally the first plants introduced were those 
of the Malayan region that were familiar to the original in- 
vaders or their successors in westei^n Malaya, and these include 
such species as Job's tears (Coix lachryma-jobi L.), the more 
common form of use for ornamental purposes, another form 
cultivated for food; sugar cane {Saccharum officinarum L.), as 
a source of sugar; lemon grass (Andropogon citratus DC), 
used as a condiment; vetiver (Andropogon zizanioides Urb.), 
for its aromatic root; sorghum (Andropogon sorghum L.), for 
food; Italian millet (Setaria italica Beauv.), for food; rice 
(Oryza sativa L.) , for food ; bamboos (Bambusa vulgaris Schrad., 
and B. blumeana Schultes), for purposes of construction; coco- 
nut (CocQs nucifera Ij^^), for food; betel-nut palm (Areca 
catechu L.), for its stimulating properties; sweet flag (Acorus 
calamus L.), medicinal; taro (Colocasia esculentum Schott), 
food; yam, "ubi" (Dioscorea alata L.), for food; garlic (Allium 
sativum L.), for food; various varieties of the banana (Musa 
paradisiaca L.), for food; various zingiberaceous plants (Kaemp- 
feria galanga L., Curcuma zedoaria L., C, longa L., Zingiber 
zerumbet Sm., and Z. officinale Rose), for condiments, etc.; 
betel-pepper (Piper betel L.) for use with the betel-nut for 
"This species is unquestionably of American origin, but reached the 
Orient long before the advent of Europeans. 
