70 On the Power of Habit in Vegetables. 



tioned, are beyond 45° of north latitude, there remains 

 no doubt, in my mind, that the plant would ripen not 

 only in Virginia, but also in Maryland (See Note 3.); 

 for although the cold of these last-mentioned countries 

 is greater in winter, the heat of the summer is very 

 little different from that of corresponding latitudes of 

 Europe. 



In connection with this subject, it may be observed, 

 that the seeds of Grasses, Clover, &c, are annually 

 carried from Pennsylvania to Virginia. By the in- 

 crease of heat, to which they are now exposed, they 

 flourish luxuriantly for a few years, but they wear 

 out, and cannot perpetuate themselves, for many 

 years, in the same perfection : at least, in the lower 

 part of the country, as about Norfolk, I know this to 

 be the case. Whether this is owing to the barren- 

 ness of soil, or to their vegetative (or vital) energy 

 being exhausted, I am not quite certain : but I rather 

 incline to the latter opinion ; for both vegetables and 

 animals become, by degrees, naturalized to the coun- 

 tries which they inhabit ; and, in the course of a few 

 generations, are but little different from the aborigi- 

 nals of the places, as far as regards their physical 

 constitutions. Some external varieties they do pre- 

 serve for a great many ages ; and if they be kept un- 

 mixed, they may never lose them ; as is the case 

 with the native Gentoos of India, and their Mahometan 

 conquerors. 



When trees, or other vegetables, are transplanted 

 into warmer climates, they arc quicker in their growth 



