58 THE TREES AND SHRUBS [LECT. 



It occurs more rarely in the south, and most fre- 

 quently near the Sperchius and Achelous, and in 

 the Olive-woods of Athens. 



The rarest species is P. tremula, which Fraas ob- 

 served only twice, namely, on the north side of 

 Parnes, behind Menidi, in a gorge 1,800 feet high, 

 and on the Achelous, behind Lithoriki. Sibthorp 

 also found it in Bceotia. 



The Lombardy Poplar, P. fastigiata, the hand- 

 somest of the species, often regarded as indigenous 

 in Europe, does not appear to have been known by 

 the ancients. 



It may have come from Persia, where it is said to 

 be very abundant, for before 1805 it had not made 

 its way even into Tuscany q . Into France it was 

 introduced in 1745, and into England about 1758. 



In spite, therefore, of the opinion of Manetti r , 

 who contends that it is native, because it springs 

 up spontaneously in places near the Po, where the 

 surface soil has been washed away by the inunda- 

 tions of the river, I think it probable that it found 

 its way into Italy since the time of the Romans. 



The same remark applies to the Horse-chesnut, 

 JEsculus hippocastanum, a tree introduced into Eng- 

 land from the Levant less than 300 years ago, and 

 indeed indigenous, it is said, in Northern Asia. 



Yet we could hardly fix upon two trees more 

 completely naturalized, and entering more fully into 

 the landscape of Northern Europe, than the Lom- 

 bardy Poplar and the Horse-chesnut. 



1 Loudon. r Gard. Mag., vol. xii. 



