64 ON THE BOTANICAL GEOGRAPHY OF THE 



cifolius ; the usual heaths, Erica cinerea and E. urn- 

 bellata. They have also many plants exclusively 

 their own, as Scilla unifolia, Hypericum linifolium 

 and several which are yet undescribed. 



The hills on the borders of the Tagus, espe- 

 cially near Lisbon, which are composed of lime- 

 stone and basalt, afford an uncommonly rich Flora* 

 We find there many plants which are peculiar 

 to North Africa ; many are common throughout 

 the South of Europe, such as the Trifolia, Medi- 

 cagines, &c. and finally an abundance of Por- 

 tuguese plants and such as are peculiarly their 

 own* 



The Cintra chain of mountains produces some 

 plants of North Portugal, some few of North 

 Europe, and some peculiar to Madeira. Hence 

 the FloTa of these mountains is very complicated*, 

 but highly interesting* 



The heaths of Alentejo are of two" sorts ; those 

 which consist of deep sand are rich in Cisti, and 

 many other plants, peculiar to these parts or other- 

 wise only to be found in North Africa. The dry 

 heaths, which have a covering of granite gravel 



