100 PLANT HABITS AND HABITATS IN THE 



latter station is hotter in summer and colder in winter and that the 

 mean annual temperature is nearly 6° F. higher than at Yongala. 

 Moreover, the mean diurnal range is nearly 4° F. higher at Farina, 

 although the maximum diurnal range at that place is but little above 

 that given for the more southern station. A somewhat similar rela- 

 tion, possibly less marked, may perhaps exist between Farina and 

 Quorn. Thus, it will be seen, Quom has cool winters and hot sunmaers, 

 with occasionally very high temperatures. 



A characteristic of the temperature of the region which should be 

 emphasized is its great daily variation. This feature, which is well 

 marked in dry regions, is of undoubted importance in its effect on 

 plants. An instance can be given which can not, unfortunately, be 

 supported by complete data. In mid-October 1918, the day tempera- 

 tures at Quorn were most agreeably cool, although it was the middle 

 of spring. Green growth and fresh flowers were everywhere and there 

 was little to suggest the brown hills of the summer to come. Particu- 

 larly the roadsides in places were masses of blue from the flowers of 

 the introduced Echium platagineum. One day late in the month 

 the wind turned to the north and brought with it the high tempera- 

 tures and the dry air of the Lake Torrens Basin. Rising to 96° F. in a 

 few hours, and with as sudden a drop in the relative humidity, the 

 arid conditions swept over the country like a flame, drying and turning 

 brown in a comparatively brief time most of the annual vegetation and 

 severely testing the resistance of the perennials. 



Vegetation and Habitat. 



The flora of the Quom region is rich in species and in individuals. 

 The mountains are clothed with a wealth of shrubs and small trees, 

 only the big outcropping rocks, often picturesquely serrated against 

 the sky, being destitute of vegetation, and the hillsides and floors of 

 the valleys are thickly covered with trees, shrubs, and lesser plants. 

 Thus the vegetal aspect of the region is quite different from what was 

 seen at Copley or in southwestern South Australia, with about 5 inches 

 less rainfall, and, as would be expected, markedly different from that 

 at Oodnadatta. It in fact compares well with the vegetation farther 

 south, where the rainfall is much greater. Quom has been settled 

 many years. In earUer times the woody plants must have been much 

 more numerous than at present and more generally distributed; but 

 otherwise the vegetation is probably not greatly changed by the advent 

 of the white man and his varied activities, and as a whole it probably 

 well represents plant adjustments under relatively arid conditions. 

 • The leading habitats in the vicinity of Quorn include the higher 

 mountains, as Devil's Peak and Mount Arden; the lower ridges, 

 some of which reach out to the Willochra Plain, the valleys between 

 these ridges, the Willochra Plain, and finally Quorn Creek and its 



