52 SUCCULENT PLANTS [CHAP. 



brine is condensed. A consequence of this is 

 that a number of wild plants growing within 

 a short distance of the erection have acquired a 

 considerable degree of fleshiness, not possessed 

 by the same species elsewhere. 1 A remarkable 

 fact is the abundance of Plantago maritima (?), 

 though the nearest sea-board is, at least, 200 

 miles distant. It may have been evolved on the 

 spot from P. Coronopus or some other species. 



As another example of adaptation, Littorella 

 lacustris may be mentioned as being closely 

 allied to the plantain (fig. 16). This has 

 become an aquatic plant, and acquired all the 

 structures found in such plants, such as air- 

 chambers, a narrow leaf, growing very long 

 and ribbon-like in deep water, just as those of 

 the arrow-head does, etc. The common figwort 

 (Ranunculus Ficaria) betrays its aquatic an- 

 cestry by having similar air-canals in the stems 

 and petioles, showing that aquatic characters 

 become hereditary, after the conditions which 

 produced them no longer exist, as the figwort 

 is now a terrestrial plant. 



The marsh samphire (Salicornea herbacea) 

 (fig. 16), common in salt marshes by the coast, 

 illustrates the succulent type of maritime plants. 



That the succulency is due to the direct action 

 of the salt is shown by the results of experi- 

 ments in which the normal fleshiness is made 



1 I collected a considerable number of these. 



