30 



PLANT HABITS AND HABITATS IN THE 



between the extreme north and extreme south of the continent of 

 Australia there is a difference of approximately 27 F. in the mean 

 annual temperature of the soil. 



It is of interest to note that the mean air-temperatures in the desert 

 are higher at parallel latitudes than those given by Taylor for longi- 

 tude 135, and probably also the mean temperature of the soil at a depth 

 of 3 feet is higher in the desert. Thus, at William Creek, 28 55' south 

 latitude, the yearly mean temperature is 68.6 F. (20.33 C.), which 

 is 2.6 higher than at latitude 30 along the longitude farther east, 

 as given by Taylor. The summer mean temperature of the air and of 

 the soil at William Creek also is quite as high as at latitude 10, 

 and the winter mean is quite as low ; in fact, it is somewhat lower 

 than the mean in the southern extremity of the continent. Thus, at 

 William Creek the course of the mean air-temperature throughout the 

 year, and probably also of the soil at a depth of one meter, is continental 

 in its range. 



Table 8 shows the estimated mean annual soil-temperatures, depth 

 one meter, at latitudes given and in regions along 135 east longitude. 



TABLE 8. 



Lat. S. 



Tropic : 



10 



15 



20 

 Temperate: 



25 



30 



35 



40 



Soil temp. 



82 

 81 

 76 



70 

 66 

 61 

 55 



