w a 
PREFACE. 
lent plants, have been moft of them, at leaft the fine forts, greatly improved by culture, they are fully 
treated of under their proper genera. 
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On this article a long feries of obfervations has been made by the author, who for near fifty years 
has applied himfelf clofely to this fubjedl 5 for as many former botanifts have enumerated a great 
number of varieties as fo many fpecies, the ftudy of botany was thereby rendered greatly perplexed; 
fome of the modem writers on this fubjedt, by going into the contrary extreme, have abridged the 
fpecies almoft as much. Indeed it muff be allowed, that afcertainiqg the real fpecific difference of 
plants, would be of great fervice to the fcience of botany ; but this cannot be done otherwife, than 
from many years experience in their culture, efpecially by obferving the varieties which arife from 
the fame feeds, as alfo the difference produced by different foils and fituations, which is frequently fo 
great as to perplex very good judges in this matter. There are likewife many other varieties which 
have arifen from feeds, faved from plants, and grown near others of a different fpecies, by which 
means they have partaken of both ; but thefe hybridine plants rarely producing any feeds afterward, 
the alteration g9es no farther. 
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