102 PLANT GEOGRAPHY 



and the cultivation of Maize, .Wheat, Oranges, the Vine, 

 the Olive, and many other fruits, serve to maintain the 

 parallelism of the two regions. 



In striking contrast to the rest of the zone in which 

 they occur are the small areas in the Northern Hemisphere 

 of what are known as the Temperate and Sub-tropical 

 Rain-forests. The former was represented in Southern 

 Japan; but, except in the temple-groves, has been 

 destroyed by cultivation. It consisted largely of lofty 

 evergreen Oaks of various species growing socially, but 

 with Camphor and other evergreen Lauracece, Camel- 

 liacece, etc., woody lianes, a few epiphytic Orchids and 

 Ferns, and parasitic LoranfhacecB ; and it formed the 

 northern limit of many tropical Indo-Malayan families, 

 such as Meliacete, Melastomacecz, Begoniacea, and 

 Piper ace ce. 



The sub-tropical rain-forest is but an extension of the 

 tropical rain-forest beyond the tropical zone, as in the 

 lowlands of Northern Mexico, Louisiana, and Southern 

 Florida. Here again evergreen Oaks (Quercus virginiana 

 Mill.) predominate, hung with the grey festoons of the 

 epiphytic Tillandsia usneoides L., and other species, 

 with climbing Aroids and Figs, Magnolias, Sabal-palms, 

 mostly dwarf, and but few woody lianes. In swampy 

 ground the Oak gives place to the Bald or Deciduous 

 Cypress (Taxodium distichum Rich.), and on sandy 

 tracts to the Pitch Pine (Pinus palustris L.) and other 

 species. 



CHAPTER II 



THE TROPICAL ZONE 



% 



AN example of the modification of heat-distribution by 

 that of moisture as striking as that above-mentioned is 

 afforded by the contrast between the tropical desert 

 regions of the globe and the rain-forest areas of latitudes 

 not greatly different. Several of the great desert regions 

 extend, it is true, considerably beyond the lines of the 

 Tropics poleward; but they are certainly in latitudes 

 where the total annual supply of heat is sufficient for all 

 purposes of plant-life. The character of their vegetation 

 is determined by the minimum of water-supply. 



