184 THE GEOGRAPHY OF PLANTS. 



tree.) On the Peak of Teneriffe, \vhich is in 

 the sub-tropical zone, this region extends tc 

 8,000 feet. On the Appenines and Alps, it 

 extends from 3,800 feet to 5,700 feet. On the 

 Harz Mountains, in Germany, it does not reach 

 beyond 3,800 feet, while in the sub-arctic zon, 

 it only ascends to 1,200 feet. 



7. Region of rhododendrons, or lower alpine 

 region, from 11,500 to 13,300 feet. The rho- 

 dodendrons, which are well known in almost 

 every garden, are the special ornaments and 

 features of this region, and abound in almost 

 every district of it in Europe. One of the 

 common species (Rhododendron ponticum) is 

 said to have been the plant from which the 

 bees of Pontus collected the honey that pro- 

 duced the extraordinary symptoms of poisoning, 

 described as having attacked the Greek soldiers 

 in the famous retreat of the ten thousand. 

 Xenophon says, that after eating it the men fell 

 stupified in all directions, so that the camp 

 looked like a battle-field strewed with corpses. 

 Dwarf species of willow also abound in this 

 region. 



8. Region of alpine plants, which grow 

 from the upper limit of the last region up to 

 the line of perpetual snow, where all vegetation 

 ceases. Most of the alpine plants are peren- 

 nial, and many of them are singularly tenacious 

 of life. Many of them are beautiful plants, 

 especially the brilliant gentians, which are the 

 glory of alpine heights ; there are some species, 

 which cover the sides of hills with blossoms of 



