PLANTS. 27 



peculiarly dangerous to human beings. The 

 surface of the ground of a mangrove swamp is 

 so soft as to render it unsafe for human feet ; 

 nevertheless, the savage natives pass over it, leap- 

 ing from root to root for miles, without once 

 daring to trust their weight upon the treacherous 

 soil beneath. 



In Asia, a maritime soil prevails very exten- 

 sively, and forms some of those vast .plains 

 called steppes, a large extent of which is strongly 

 impregnated with salt, and here only maritime 

 and saline plants will flourish. These steppes 

 extend over a space of about a million square 

 miles, exclusive of the extensive frozen marshes 

 of the north of Siberia, and extend from the Sea 

 of Azov and the Ural Mountains on the west, to 

 the little Altai Mountains and the Lena on the 

 east. The vegetation upon them consists of 

 comparatively few species, and those are stunted; 

 among the most conspicuous are the sea laven- 

 der, (Statice tatarica,) a species of salt-wort, 

 (Salsola prostrata,) some species of liquorice, 

 (GlycyrrMza hirsuta, and G. Icevisj) the latter 

 the liquorice-root of our shops, with some 

 others. On our own shores, the eryngo, 

 (Eryngium maritimum,) with its beautiful blue 

 heads of flowers and bluish- white foliage, forms 

 a striking object. 



Sand plants are those which thrive, alone or 

 nearly so, in silicious sand. They are of a 

 peculiar character in all parts of the world, and 

 the greater number are probably grasses and 

 their allies. Three of these plants especially, the 



