42 PLANTS OF NEW ZPZALAND 



Plants which liave been evolved in soils containing more 

 than a half ^er cent, of salts in solution, are termed haloplujtes. 

 Such plants are found chiefly near the sea-shore, by river 

 estuaries, or in salt marshes. They sometimes occur also in 

 desert areas, particularly in the dried-up beds of salt lakes. 

 They often bear resemblances to xerophytes. The water of 

 salt-meadows is apparently not readily absorbed by plants, and 

 consequently such situations may be physiologically dry. 

 Probably the presence of salts in solution interferes with the 

 passage of moisture by osmosis into the plant cells. A fuller 

 consideration of the structure of halophytes will be found under 

 the family Chenopodiaceae. 



Hydrophytes are plants which have been produced amidst 

 abundance of water of moderate temperature, and in the 

 absence of an excessive amount of dissolved salts. They will 

 be further considered under MyriopliylJuDi. Mesophytes, 

 on the other hand, are plants whose structure indicates that 

 they have been developed in intermediate conditions, where 

 there was neither saturation with moisture, nor was there 

 drought. Mesophytes frequently lose their leaves at the end 

 of the growing season, and often die back to the ground. 

 Amongst them are a large number of annuals, bulbous, and 

 tuberous plants. New Zealand has remarkably few mesophytes. 

 Trees such as Entelea Sbnd Aristotelia >'«cewosa are mesoph3'tic, 

 but dicotyledonous herbaceous mesophytes are almost com- 

 pletely absent from New Zealand. We have scarcely any 

 annuals, and very few bulbous plants. It is due to lack of 

 them that our lowland pastures and hedgerows do not display 

 in spring and early summer such brightness of colour as is 

 to be seen in many other lands. 



