196 INTRODUCTION TO PLANT GEOGRAPHY [CHAP. 



(9) South Atlantic — distributed at least in South America and 

 Africa (often including Madagascar), as in the case of rather numerous 

 genera including Asclepias (Milkweeds, or Silkweeds), see Fig. 57. 



(10) Antarctic — distributed on the antarctic mainland (usually 

 as fossils) and in the southern parts of South America, New Zealand, 

 or on some other austral island or islands, as in the case of the 

 genus Nothofagus (the so-called ' Beeches ' of the southern hemi- 

 sphere), see Fig. 58. 



These ten major types do not by any means cover the detailed 

 diversity of discontinuous areas even of an intercontinental nature. 



Fig. 59. — Map showing (bipolar) range of the genus Empetrioii (Crowberries). 

 (After Good, emended.) 



Thus in the general category there is the ' bipolar ' type mentioned 

 earlier, an example of which is afforded by the genus Empetrum — 

 see Fig. 59. Other well-known examples are aflForded by certain 

 Sedges. Also involving parts of more than one continent is the 

 * Gondwana ' type which, in conformity with the palaeogeographical 

 basis of ' Gondwanaland ', tends to embrace Africa, Madagascar, 

 India, and Australia. 



Even more numerous than the above are the types of discontinuous 

 range of an m^racontinental nature, as for example in Australia 

 where the section Erythrorhiza of the genus Drosera (Sundews) 

 affords a striking example as indicated in Fig. 60, or in southwestern 

 Europe with the ' Lusitanian ' element in the British flora. This 

 last element is composed ideally of plants which grow in oceanic 



