THE PALAEOTROPICS 185 



As in most tropical forests, the Leguminosae are among the 

 commonest of the lianas. Among these are species of Mucuna, 

 Pueraria, Bauhinia, Entada, while the Vine family, is represented 



by a number of species of Vitis; Peppers, Ipomoeas, Bignonii 



and big-leaved Araceae form great cables looped from tree t<> ti 

 or clamber up the trunks and branches of the lower trees and 

 shrubs. Rattan-palms of several species are characteristic, and 

 some of these reach into the temperate zone up to 7,000 feet. 



The screw-pines (Pandanus), with leaves 8 to 10 feet long, and 

 bamboos of several sorts, are striking features of the vegetation. 

 The bamboos are especially abundant in the Himalayan forest, 

 and many species extend into the temperate zone. Some of these 

 are gigantic, sometimes a hundred feet high. 



Ferns are abundant, and include some fine tree-ferns (Also- 

 phila sp.) as well as many epiphytes, and epiphytic orchids are 

 common, some of them of great beauty. 



Above 3,000 feet the tropical forest shows an increasing number 

 of temperate species which become predominant above 4,000 

 feet x and from this elevation to Darjiling (7,000 ft.), the flora 

 has much in common with the temperate floras of Eurasia and 

 North America, especially the Atlantic States. 



Assam and Upper Burma 



Northeastward from Bengal, and continuous with the tropical 

 Himalayan forest belt is Assam, which includes the valley and 

 delta of the Brahmaputra, and a series of mountain ranges with 

 their intervening valleys. It is a region of excessively heavy rain- 

 fall, and the rain-forest of the valleys and lower hills is an east ward 

 extension of the lower Himalayan forest zone, and reaches further 

 eastward into Burma and Indo-China. 



This forest, however, while made up largely of Indo-Malayan 

 tropical genera, also, especially at higher elevations, as in the 

 Himalayas, has many species of northern rather than tropical 

 affinities, such as oaks, chestnuts, camellias, and others. The 

 whole of this region lies within the monsoon belt. i. c, it has a more 

 or less pronounced dry season, and a considerable number of 

 deciduous trees. 



1 Hooker, loc. cit., pp. 95-100. 



