he vegetable system. 
27 
This Xanthium, therefore, is a proof that there are Plants common 
to America, and to the other parts of the world ; nor is it the only one 
by many. The queftion fo long difputed, feems capable therefore 
of a tolerably fair decifion. 
Upon the whole, it feems that there are fome Plants, though not 
many, which are common to Europe and to North America; and 
that there are many common to South America and Alia. 
With refpedf to the North American, there are befide thofe already 
named, a Conyza, common to that country, and the Pyrenaean moun- 
tains, and fome others. I had laft year an opportunity of feeing, 
beyond conteft, that fome Modes, common on Hampftead Heath, 
grow alfo in America. Mr. Gray, Seedfman, in Pall-Mall, received 
many Plants from thence, in a condition of growth, and their roots 
were covered with the Great Hypnum, the Bog Sphagnum, and two 
or three other kinds frequent there. 
Rash obfervations might add vaflly to the lift of Plants ; for Plan- 
tain, Sorrell, and many other common things in our paftures, are as 
frequent about our Plantations there : but the Seeds of thefe have 
doubtlefs been accidentally carried over from hence ; and in this en- 
quiry, great diftindlion is to be obferved between fuch Plants and the 
proper natives. 
With refped to the products of South America, which are common 
to Afia, there is alfo to be great caution ufed, to find out from their 
place and other accidents, which are native, and which have been in re- 
ality brought thither from Afia: for we very well know that the firft 
fettlers in South America, were very intent on railing in the Weft-In- 
dies, the products of the Eaft. However, if we leave out of the ac- 
count, fuch valuable articles, we fhall find ftill a great number, which 
men could never be interefted to carry over, and which are in places 
far from fettlements. The Coftus of Ceylon, is found alfo in Surinam 
and the Brafils ; the Canna is common to Coromandel and Jamaica; 
and Feuille’s Alkekengi is equally common in Peru and Borneo. 
D 2 
We 
