86 THE GEOGRAPHY OF PLANTS. 



of known poisons. The kernel of the fruit, 

 though not larger than an almond, is suffi- 

 cient to destroy twenty people. It was used 

 in Madagascar as an ordeal, but is now discon- 

 tinued. 



3. The Sub-tropical Zone extends from the 

 tropics to 34 N. or s. lat. Its mean tempera- 

 ture is from 62 to 69 Fahr., and with an 

 average summer heat of from 73 to 82. Its 

 climate is one of the most delightful on the 

 globe, and many of the tropical fruits, with 

 many plants which properly belong to the equi- 

 noctial zone, are found in it, while the winters 

 are so mild that man scarcely needs the sub- 

 stantial dwellings of colder climes. It embraces 

 the north of Africa, including the Great 

 Desert, Morocco, Barbary, Algiers, Tunis, Tri- 

 poli, and Egypt ; in Asia, Palestine, Syria, the 

 north of Arabia, Persia, Cabul, Beloochistan, 

 Thibet, the north of India and China ; the 

 southern part of Australia ; South Africa ; 

 Paraguay, La Plata, Chili, Banda, in South 

 America ; the Bahamas, Bermudas, Mexico, 

 Texas, the Southern States, and California, in 

 North America. The vegetation of this zone is 

 very interesting and very important. Like the 

 damper regions of the tropical zone, the plants 

 are green all the year round, A number of 

 succulent plants, of the house -leek, stone- 

 crop, Mesenibryanthemum, and other tribes, are 

 distinguishing features of this zone, especially 

 in Africa. Many of them have beautiful 

 fiowers, while their thick, succulent leaves, with 



