INFLUENCE OF WATER ON LAND-PLANTS 37 



exposed to the sun are always smaller than those which 

 develop in partial shade, and the dwarfing of plants 

 in exposed situations is due, in part at least, to this 

 effect. 



Another kind of stunted growth is the rosette-iorm., 

 characteristic of many plants living in regions either 

 permanently or periodically dry or cold. The rosette- 

 form, however, is permanent ; it is iaherited, and there- 

 fore independent of circumstances. In a rosette-plant — 

 e.g., London-pride (Fig. 5), the stem, through the sup- 

 pression of the internodes, does not elongate, but bears 



Fio. 5. — Lonbon-Pbidb, showino Rosbtte-Habit. (Natueal Size.) 



a number of closely-set radiating leaves close to the 

 ground. These leaves provide a deep shade under which 

 no other plants can grow, and in this way the plant frees 

 itseK from competitors. The soU, being shaded, tends 

 to remain moist beneath the leaves, and, as the stomata 

 are found on the under surface, transpiration takes place 

 in moist shade, and is therefore not excessive. 



Rosette-plants are common, not only in alpine regions, 

 but in all grassy places where the herbage is low, and 

 tall weeds are in danger of desiccation by violent winds. 

 The presence of rosette-plants {e.g., dandelion, daisy, 

 plantain) in a damp meadow might appear to conflict 



