DISTRIBUTION OF PLANTS. 117 



cann), Hazelnut (Corylus avellana), and Alder (Alnus glutinosa), 

 the former nevertheless must be regarded as the immediate 

 ancestors of the latter respectively. 



11. The regions into which this division (North Extra- 

 tropical) have been separated are as follows : (a) Arctic ; (6) 

 Subarctic or Coniferous ; (c) Middle European and Ural-Cas- 

 pian ; (d) Central Asiatic ; (e) Mediterranean ; (/) Manchu- 

 rian-Japanese ; (g) Pacific North American ; (K) Atlantic North 

 American. These regions are divided into provinces ; those 

 for the Atlantic North American being the Appalachian and 

 the Prairie. The first lies east of the Mississippi. It is pre- 

 eminently a forest region, having numerous representatives of 

 such genera as Quei-ats, Juglans, Hicoria, Magnolia, Finns, Ju- 

 niperus, etc. The other province (the Prairie) lying west of the 

 Mississippi is covered with many species of grasses. The low 

 characteristic ones belong to the genera Bouteloua (Mesquite 

 grass), Bulbilis (Buffalo grass), etc. Farther westward and 

 southward are found various species of Cactus, Yucca, Agave, 

 etc. 



12. The Paleotropical division includes Central and South- 

 ern Africa (except a part of Cape Colony), southern Asia, the 

 northern and eastern coast-region of Australia, and all of the 

 islands lying immediately northward. It is composed of the 

 following regions : (a) West African ; (6) Africo- Arabian ; (c) 

 Madagascar and Islands ; (c?) Indian ; (e) Tropical Himalayan 

 (a narrow area extending southward from the point where the 

 Brahmaputra cuts through the Himalayas) ; (/) East Asiatic ; 

 (g) Malay ; (A) Araucarian (eastern border of Australia), New 

 Caledonian and the northern island of New Zealand ; (i) Poly- 

 nesian ; (j) Sandwich Islands. 



13. The Neotropical division includes Mexico, Central 

 America and the greater part of South America — excluding 

 the Chilian coast south of latitude 35 degrees, and Terra del 

 Puego. The regions into which it is divided are : (a) Mexican 

 tablelands ; (6) Tropical American (including the Provinces : 

 West Indian, Sub-Andean or Panama with parts of Colombia 

 and Venezuela, North Brazil-Guianan and South Brazilian), 



