SURVIVAL OF ORGANS 



297 



2. INSIGNIFICANCE OF THE RUDIMENTARY ORGAN. 

 It frequently happens that rudimentary organs are 

 preserved simply on account of their insignificance : 

 the absence of organs so small would not be an 

 advantage to the plant sufficiently great to be laid 

 hold of by natural selection. 



Many species of Tropaeolum bear leaves without 



FIG. 84. Two seedlings of Phyllanthus speciosus. 

 1, 2, 3, 4, successive assimilating branches ; c, cotyledons. 



stipules. In Tropaeolum majus there are stipules 

 only in the case of the first two leaves of the 

 seedling, and the position of these stipules is very 

 variable. Sometimes both stipules are at the base 

 of the petiole ; sometimes only one is present ; 

 sometimes both are several millimetres from the 

 base a position in which functional stipules never 

 occur. 



