114 KEARNEY: PLANT LIFE ON SALINE SOILS 



mention. Oliver^i and other British ecologists have investigated 

 the manner in which Spartina, Sahcornia, etc., colonize and hold 

 newlj^-deposited soil on the sea-coast. Vaughan^- gives an in- 

 teresting account of land-building by the mangrove in southern 

 Florida. 



Halophytic vegetation is characterized by world-wide uni- 

 formity. Each of the principal types — salt marsh, salt scrub, 

 and the mangrove formation — has much the same appearance, 

 wherever it occurs. The comparatively small number of species, 

 the similarity of the life forms, and the scarcity of showy flow- 

 ers give a monotonous and even somber appearance to these plant 

 formations. 



In taxononlic composition, likewise, there is comparatively 

 little variation within each of the major halophytic formations, 

 in different parts of the world. The genera, and in many cases 

 even the species, are very widely distributed. The great ma- 

 jority of extreme halophytes are comprised in comparatively 

 few families. Probably not less than one-half of the species 

 belong to the Chenopodiaceae, which comes nearer to being a 

 purely halophytic group than any other of the larger families of 

 plants. Smaller families which are predominantly halophytic 

 are Plumbaginaceae, Frankeniaceae, Tamaricaceae, and Rhizo- 

 phoraceae. Families which, although not primarily halophytic, 

 contribute numerous genera and species to this vegetation are 

 Gramineae, Cnaciferae, and Compositae. Other large groups 

 are conspicuous for their absence from saline soils. Among 

 these are the lichens, mosses, ferns, Araceae, Orchidaceae, Fa- 

 gaceae, and Ericaceae. 



STRUCTURE OF HALOPHYTES 



As a rule, the leaf surface of haloph3^tes is much reduced as 

 compared with that of mesophytes. In Salicornia and allied 



" F. W. Oliver. The shingle beach as a plant habitat. New Phytol. 11: 73. 

 1912. Some remarks on Blakeney Point, Norfolk. Journ. Ecol. 1:4. 1913. 

 Vegetation and mobile ground as illustrated by Suaeda ffuticosa on shingle. Journ. 

 Ecol. 1:249. 1913. 



1- T. W. Vaughan. The geologic work of mangroves in southern Florida. 

 Smiths. Misc. Coll. 5: 46L 1910. • 



