WATER CONTENT OP PLANT AND SOIL 



31 



apparently dies with a much higher per cent of water than 

 a woody one, although its death usually takes place more 

 slowly. The roots of Coleus and Nasturtium die before the 

 stems, but after the root is dead and dry the plants will not 

 recover although there may be 50 per cent of water remain- 

 ing in the stems. Lobelia syphilitica usually begins dying at 

 50 to 70 per cent and is usually dead at 40 per cent. 



The following results indicate the difference between some 

 rosette plants of hydrophytic tendencies in the amount of 

 water in the soil and plant when the plant is dying, and the 

 amount in rosettes of xerophytic tendencies. The plants 

 were grown in loam in the plant house. 

 Lobelia syphilitica. 



Average with Six Species of Xerophytic Tendencies. 



From this and similar results obtained, it was found 

 that hydrophytism tends to make a plant more sensitive to 

 excessive water loss, so much so that it dies with a greater 

 per cent of water in its tissues than in the soil. The hy- 

 drophytic plant usually has more water in its tissues when 

 turgid and it is to be expected that it might die with a 

 slightly greater relative per cent of water, both in the plant 

 and in the soil. Other variations of the water in dying 

 plants will be discussed under the next section. The fol- 

 lowing tables give results from three species, one of xerophy- 

 tic tendencies, one of hydrophytic tendencies, and a meso- 

 phytic grass, all grown in loam in the plant bouse. 



