164 PHARMACEUTICAL BOTANY 
the plants are accustomed to live which may be aquatic, meso- 
phytic, halophytic or xerophytic, etc. 
Aquatic plants or hydrophytes are those which live in water or 
wet soil as the water-lilies, calamus, cat-tails, etc. 
Fic. 98.—Root systems. Fleshy tap root of Carrot (1); napiform root of a 
Radish (2); multiple, tuberous roots of a Dahlia (3); nodose roots of the Dropwort 
(4); fibrous roots of a Grass (5); fibrous-tuberous root system of an Orchid (6). 
Mesophytic plants or mesophytes are those which thrive with a 
moderate supply of moisture, as most of the land plants of our 
fields and meadows. 
Halophytic plants or halophytes are those which thrive in salt 
marshes, on saline flats near the sea coast and on the alkali flats of 
the interior, as the salt marsh samphire, the mangroves, cheno- 
podium, etc. 
Xerophytic plants or xerophytes are those which thrive in very 
dry soil, as the cactus, century plant, hemlock, spruce, etc. 
