THE FLORA OF WESTERN CHINA 5 



it is convenient to divide the region into altitudinal zones 

 or belts. The mountainous nature of the country lends itself 

 admirably to such an arrangement, and it is perhaps the only 

 feasible way of dealing with a subject so vast and unwieldy. 

 The chart (p. 7) represents an ideal section of the region and 

 may possibly convey a clearer idea of the subject than the 

 text which follows : — 



Division i. — " The belt of cultivation — 2000 feet altitude." 

 The climate of the Yangtsze Valley, up to 2000 feet altitude, 

 is essentially warm-temperate. Rice, cotton, sugar, maize, 

 tobacco, sweet potatoes, and legumes are the principal summer 

 crops ; in winter, pulse, wheat, rape, hemp, Irish potato, and 

 cabbage are generally grown. It is a region of intense culti- 

 vation and the flora is neither rich nor varied. The following 

 wild plants are characteristic : Bamboos [Bambusa arundinacea, 

 Phyllostachys pubcsccns, and other species) , Fan Palm [Trachycar- 

 Pus excelsus), " Pride of India " [Melia Azedarach), Crepe Myrtle 

 {Lagerstrcemia indica), Winter Green [Xylosma racemosum, 

 var. pubescens), Chinese Banyan [Ficus infectoria), Gardenia 

 {Gardenia florida), Roses [Rosa Icevigata and R. microcarpa) , 

 Nanmu [Machilus nanmu and other species). Pine {Pinus 

 Massoniana), Soap tree [Gleditsia sinensis), Alder {Alnus 

 cremastogyne) .Vrivet [Ligustrum lucidum), Paulownia Duclouxii, 

 oranges, peaches, and other fruit trees, ferns, especially 

 Gleichenia linearis, weeds of cultivation, miscellaneous shrubs 

 and trees, including Pterocarya stenopter a, Celiis spp., CcBsalpinia 

 sepiaria. Wood Oil [Aleurites Fordii), and Cypress {Cupressus 

 funebris) ; the last two occurring particularly in rocky places. 



Division 2. — " Rain forests belt — 2000 to 5000 feet altitude." 

 Between 2000 and 5000 feet are found rain forests, consisting 

 largely of broad-leaved evergreen trees, mainly Oak, Castan- 

 opsis. Holly, and various LaurinecB. The latter family con- 

 stitutes fully 50 per cent, of the vegetation in this zone. Ferns, 

 evergreen shrubs, Chinese Fir {Cunninghamia lanceolata) , and 

 Cypress are other prominent components. This belt is inter- 

 esting also as being the home of nine-tenths of the monotypic 

 genera of trees that are so prominent a feature of the Chinese 

 flora. The more interesting of these are : Eucommia, Itoa, 

 Idesia, Tapiscia, Sinowilsonia, Platycarya, Davidia, Carrieria, 



