42 PLANT HABITS AND HABITATS IN THE 



The most interesting feature of the country is the River Murray. 

 The Murray and its tributaries drain the western slopes of mountainous 

 eastern and central Queensland, New South Wales, and Victoria. In 

 favorable seasons, with its main tributary, the Darling, it can be 

 navigated for 2,000 miles. At Blanchtown at high-water (as in 

 October 1918) the river is approximately 600 feet wide. The vertical 

 variation between the summer level of the river and the winter-flood 

 level is 20 feet or more. In the area considered it does not overflow 

 its banks and it has no direct and immediate effect on the native flora 

 along its shores. 



5LIMATE. 



xX^ 



Temperature, 



rSouth Australia enjoys a mild temperate climate. The lowest 

 tlSnperature recorded up to 1912 was at Mount Barker, 24.3° F., 

 and the highest recorded shade temperature was 119° F. at William 

 Creek, in the far north, about midway between Maree (Hergott Springs) 

 and Oodnadatta. The former is near the southern termination of the 

 Central Highlands and the latter is in the Lake Eyre Basin. Except 

 in the more arid districts the seasonal and the diurnal variations are 

 not extreme. 



The 65° F. isotherm enters the state sUghtly south of the center of the 

 eastern border, curves to the north in crossing the Central Highlands, 

 dips south in the Lake Gairdner Basin, and, taking a northwestern 

 direction, reaches the highlands in the extreme northwestern portion 

 of the state. Here it is again deflected sharply north and leaves the 

 state not far from the northwestern comer. About 64 per cent of the 

 entire area of South Australia is within the 65° to 76° F. isotherms. 



The really great difference in the apparent amount of heat received 

 by the northern and mainly arid (as contrasted to the southern and 

 mainly humid) portions of the state is further suggested by the number 

 of days in each in which the thermometer registers a shade temperature 

 of 90° F. or more. At William Creek, for example, there are on the 

 average 114 days in each year when the thermometer registers a 

 temperature of 90° F. or over, while, on the other hand, at Adelaide, 

 which is by no means the coolest southern station, the number of 

 days in which the thermometer shows this temperature is only 43 in 

 the year. This may not mean, however, that there is a corresponding 

 difference in the amount of heat units actually received between the 

 two stations, since there are nearly three times as many nights, 40 as 

 against 14, during which the thermometer records a temperature of 

 40° F. or less at William Creek, as opposed to night temperature at 

 Adelaide. Here again the temperature at Adelaide probably does 

 not represent the extreme condition, but reveals the steadying in- 

 fluence of the Southern Ocean, near which the city is situated. 



