84 



PLANT HABITS AND HABITATS IN THE 



dant vegetation, to establish not only the amount of rainfall but its 

 distribution through the year. Very little is accurately known as to 

 the rainfall at Ooldea, for the reason that permanent settlement began 

 only with the building of the transcontinental railway, which was 

 opened late in the year 1917. There are, however, records for one 

 year at a railway camp a few miles to the east and for nearly one year 

 at Ooldea itself. In addition, rainfall reports are available for Fowler's 

 Bay to the south and at Tarcoola to the east, covering many years. 

 Nothing is known regarding the rainfall on the Nullarbor Plain except 

 from inference. The precipitation for the years 1917 and 1918 at 

 396-mile Siding and at Ooldea, supplied by the Bureau of Meteorology 

 of the Commonwealth, is given in table 14. 



No record where is given. 



Beyond the general facts that the summers at Ooldea are very hot 

 and the winters are cool, Uttle is known of the temperature. Although 

 80 miles, or more, intervenes between Ooldea and the sea, it is prob- 

 able that here, as at Tarcoola, where the distance is even greater, the 

 southern winds are cool in summer and cold in winter, and that the 

 converse is true of the winds from the opposite direction. Such winds, 

 moreover, are undoubtedly of very great importance as factors modify- 

 ing not alone the temperature but also the relative humidity of the air, 

 and thus they very directly affect the vegetation. This had already 

 been mentioned in the opening section and need not be further dwelt 

 on in this place. 



Habitats. 



During my short stay at Ooldea, besides exploring on foot its 

 immediate neighborhood, I visited, through the kind assistance of 

 Mr. Edwards, engineer in charge of construction, such localities as 

 were most accessible from camp by motor car (railway), carriage, or 

 saddle-horse. Thus the localities seen included the eastern side of the 

 Nullarbor Plain, the transition between the plain and the sandhills, 

 and the sandhills including the (1) Ooldea Soak, (2) the "oak" forest 6 

 miles south, (3) the Condensers and Station 408, together with the 

 region traversed between Ooldea and the last two, and (4) the vicinity 

 of Ooldea itself. It will be seen that there are at least three easily 



