1912] BRIGGS & SHANTZ—WILTING COEFFICIENTS 235 
were taken from the water and grown in the air without being 
permitted to develop new leaves. This plant also had a poor root 
distribution. If we except Jsoetes, the other hydrophytes give a 
mean wilting coefficient identical with that of the mesophytes. 
The xerophytes tested gave a mean ratio intermediate between the 
hydrophytes and mesophytes. This would indicate that plants 
native to dry regions are unable to reduce the water content of the 
soil to a lower point than is reached by other plants at the time of 
wilting. 
TABLE II 
THE RELATIVE WILTING COEFFICIENT FOR DIFFERENT PLANTS 
PROBABLE ERROR 
PLANT No. OF MEAN RATIO 
Of mean ratio | Of single ander 
Vesey tee yes aaa. 75 I.03 0.003 O42 
sie Gig a ky eee as 66 0.98 0.008 0.062 
Chactochtoa Halen oo ct 4 .O7 0.006 * 0.035 
EURACHIR 3% ici, Pe OS 653 0.904 0.002 0.049 
Lite: ge age Sepsis ots eet we Te 46 0.995 0.007 0.047 
Bondi es as 60 0.97 0.006 0.047 
OCR gr ee 19 0.94 0.011 0.049 
hah eee eee re eae Oe at .04 0.012 0.054 
MARNIE 65 i a 77 0.97 0.005 0.040 
PEPUININMEE Se set ue 138 I.O1 0.005 0.059 
Cucurbitatese 24.0.5 006.0 02.3: 2 0.99 0.016 0.068 
Siyoupersigoy oe 6 ko 20 1.06 0.009 0.040 
Concetie SS Eig Gn 19 14 ©.005 °. 
Fiydrophytes: 6.9069 oe 8 I.10 0.037 0.105 
BACHE ii ae 35 1.02 0.010 0.058 
POOR VERS eo ee 16 x. ° 0.032 
Total number ig observations. . T3918. dh a ae ee 
Weighted ean! oS i es : E00 ee a eae 
The results of the different crops have been summarized in table 
II without reference to varieties. Reference to the table will show 
that only slight differences exist among the various crops in their 
ability to reduce the soil moisture content before wilting occurs. 
Sorghum, millet, wheat, oats, barley, and the grasses are practically 
the same. Rye and rice appear to be a little lower than the mean, 
corn and the legumes slightly higher. 
U.S. DEPARTMENT OF AGRICULTURE 
BurEAvU OF PLANT INDUSTRY 
Wasaincton, D.C. 
