Australian Flowering Plants. 175 



and inland plant types. The greater portion of Australia, 

 west of the Eastern Australian plateaus, possesses really only 

 two well-marked seasons, namely summer and winter. The 

 highest shade reading recorded is about 127 degrees Fahren- 

 heit, and the lowest winter reading from 10 to 15 degrees ; 

 moreover, the humidity is remarkably low in these great plains 

 or low plateaus. Exceptions occur in the southwestern corner 

 of Australia and in the Port Darwin area in the Northern 

 Territory. The eastern plateaus are well watered but are 

 subject to desolating winds both in summer and winter and 

 temperatures considerably below zero Fahrenheit have been 

 recorded from southern localities. These plateaus, however, 

 afford shelter to the coastal region from the desolating winds 

 of summer and winter, especially to those portions immediately 

 under the escarpments and in the gorges. This narrow coastal 

 strip supports an assemblage of plants of the jungle habit 

 crowded together, interlaced with vines, and having a great 

 similarity to Malayasian types, and to a lesser degree with types 

 found distributed over the whole of the fertile tropics. 



In the subarid to arid regions which comprise so great a 

 proportion of the Australian area, there exist numerous spe- 

 cialized xerophytes of the families Leguminosse, Myrtacese, 

 Myoporaceaa, Euphorbiaceaa, Verbenacese, Labiatse, Compositse, 

 Santalacese, Rhamnacese, Graminacese, Chenopodiacese, Mal- 

 vaceae, and Sterculiacese. 



But the most instructive feature in the distribution of the 

 Australian flora is the great number of genera and species, and 

 the individuals innumerable of such genera and species on the 

 large and excessively sandy areas lying mainly between 28° 

 and 42° south latitude, and especially in the southwestern 

 corner of West Australia between 29° and 34° south latitude 

 where the rainfall is fair in amount but not great, where the 

 summers moreover are very hot and the continental winds from 

 the center are very dry. Large patches of sandy soil occur in 

 the Sydney-Blue Mountain area, and in the northeastern por- 

 tion of New South Wales, but there the rainfall is greater, 

 tbe temperature more uniform, and the effect of the desiccating 

 continental winds much less pronounced than in the western 

 area. Nevertheless the numbers of genera and species are 

 greater in the sandy southwestern area of Australia than in 

 the well-watered sandy tracts of eastern New South Wales. 



On these sandy wastes are to be seen not only the great 

 proportion of the endemic genera of Australia, but also the 

 large genera of Australia. Certain important subgenera or sec- 



