DEVELOPMENT AND DISTRIBUTION OF LEGUMINOS. 365 
The xerophytes with their phyllodes, cladodes, leaves hung 
vertically, woolly surfaces, bulbous rootstocks, and their 
leathery leaf cuticles, all calculated to diminish transpira- 
tion in barren sand, sub-alpine swamps, saline coastal soils. 
or deserts, would be handicapped by such structures in 
regions of prolonged rainfall, abundant shelter and rich soil. 
Moreover, being lovers of the direct rays of the sun, and 
being of diminished height, they would be strangled and 
suffocated by the twining and towering canopy of the 
jungle. In the jungle, then, the struggle is for light and 
food and the tendency there for the Angiosperms is to pro- 
duce tall trees or great climbing twiners, with abundance 
of luxuriant foliageas opposed to the tendency of xerophytes. 
to become dwarfed, and with a limited food supply, to 
develop into numerous species and toexercise their strength 
in the production of abundance of fruit and seeds rather 
than magnificence of the individual. 
This great vitality of xerophytes, within appropriate 
limits, is exemplified well in the distribution of Leguminosze 
and Myrtacez, in both the subarid as well as the more 
barren and sandy portions of Australia, also in the distribu- 
tion of Leguminosz both in sub-arid South Africa and in 
the waste places of Hurope and Asia. This has led the 
majority of botanists to consider the tropical Mimosee,, 
and Ozesalpiniez, as of relatively recent development, while 
at the sam time, it has led them to consider forms such as. 
Kucalyptus, the Australian Podalyriez, the South African 
Genistez, and the extratropical Galegee, as of great age. 
Nevertheless, in a former chapter, it has been shown that 
the evidence both of the geographical distribution and the 
plant morphology suggests that types such as Acacia and 
Cassia were in existence before any of the existing Poda-. 
lyriee, or Genisteze, with the exception of the tropical 
Crotalaria, and before any of the xerophytic Galegez or 
