oS FLOWERING PLANTS 
CHAPTER IT 
ECOLOGICAL CLASSIFICATION OF PLANTS 
Flowering F'Rom the point of view of ecology, Flowering 
Plants Plants may be arranged in three well-marked 
classified ; g 
according STOUDS - 
to Habitat. |. Hydrophytes (Gk. hydor, water, and phyton, 
a plant), or Water-Plants. All plants which live entirely in 
water, or in soil containing 80 per cent. water, are by Tame 
ing included in this group. 
II. Xerophytes (Gk. Xeros, dry, and phyton, a plant). These 
plants grow either on rocks, or in a soil which through the 
greater part of the year is poor in water, never having more 
than 10 per cent. The British Xerophytes are chiefly alpine 
or seashore plants (Halophytes, Gk. hals, salt). The con- 
ditions under which these two groups of plants grow are 
practically similar ; the dryness of the mountain air and the 
salt of the sea air have the effect of increasing transpiration, 
whilst the salt in the soil tends to lessen absorption. These 
plants have to protect themselves from too great transpiration. 
III. Mesophytes (Gk. mesos, middle). These occupy an 
intermediate position, and include all plants that are neither 
hydrophytic nor xerophytic. They like a good regular or | 
seasonal rainfall, and a soil more or less rich in humus. By 
far the larger number of British plants belong to this group ; 
they include not only the herbs of our hedgerows, meadows, 
woods, and moors, but also the majority of our shrubs and 
trees. | | 
Character.  Vater-Plants include those that live entirely 
istics of submerged in water and those that may be de-— 
Hydrophytes. scribed as amphibious, living partly in and partly 
out of the water. The conditions of life lived under water 
are peculiarly favourable to growth and multiplication. To 
