ARID PORTIONS OF SOUTH AUSTRALIA. 57 



GENERAL FEATURES OF FLORA OF SOUTH AUSTRALIA, 

 THE NORTHERN PORTION OF SOUTH AUSTRALIA. 



The flora of the northern portion of South Australia has a marked 

 xerophytic stamp. As much, however, can be said for most of the 

 perennials, if not all, in other portions of the state having a much 

 larger rainfall. As Taylor remarks, possibly with another idea in mind, 

 "it differs in degree according to the rainfall, but not in kind" (1918:89). 

 This is possibly the most remarkable feature of the vegetation of this in- 

 tensely dry region. That is to say, there are possibly no perennial forms 

 peculiar to it as such — for example, as the different types of succulents 

 developed in other arid and semi-arid regions, or possibly in regions 

 which are desertic. There also are apparently no deciduous species. 



In other dry regions some of the species are deciduous. For 

 example, the acacias of the Sahara, as well as those of the south- 

 western United States, have foliage which falls away with the seasons; 

 and in the arid southwestern part of the latter country a species 

 (Fouquieria splendens) occurs which is deciduous with respect to the 

 occurrence of the rains, losing and forming the foliage perhaps several 

 times during the year, in a manner directly connected with the rains 

 and the intervening dry spells. Therefore, there may be possible 

 not -a little variation in plants in extremely arid regions. Thus, 

 although the perennial flora of the far north has apparently Httle or 

 no striking peculiarities which set it apart from that of the regions of 

 South Australia more highly favored with rainfall, there is still not a 

 little diversity in it. 



Among the most interesting trees of the dry region are several 

 species of Acacia which show important morphological, as well as 

 physiological, differences. Certain of the hakeas exhibit remarkable 

 differences as between species and marked adjustment to an arid 

 envu-onment. Of the shrubs, those of the genus Eremophila are of 

 especial interest. Out of the 39 species, including those now put 

 under PhoUdia, Tate gives 17 species as occurring in the northern 

 portion of the state. Of the shrubs, this is the desert plant par 

 excellence. But the halophytes of whatever species constitute the 

 most prominent element of the flora of this region. Tate gives 54 

 species of the Chenopodiacese and Amarantacese from the far north, 

 most of which are highly salt-resistant. There are a few succulent 

 annuals, or half shrubs. Among these are species of the Zygophyl- 

 lacese and Calandrinia halonnensis (Portulacese) ; the latter bears large, 

 succulent leaves and is much sought after by animals. Stuart's pea, 

 Clianthus dampieri, is one of the most showy of the annuals. 



Of the grasses, among the most frequently met are the "bunch" 

 forms, as Triodia irritans and Spinifex paradoxus, which are widely 

 distributed in the interior of the continent. In addition, according to 



