ARID PORTIONS OF SOUTH AUSTRALIA. 59 



The effect is as if no living thing ever found or ever could find a lodg- 

 ment and an abiding-place in the expanding waste. More careful 

 examination, however, reveals the presence of plants. Across the 

 lower plain, for example, there extend narrow ribbons of vegetation. 

 These converging make gray-green bands and mark the drainage 

 channels where only masses of vegetation are to be found. The in- 

 consequential plant life of the plains as a whole does not appear on such 

 a general view. Slight as is the present-day vegetation of the region, 

 it perhaps is a matter for surprise that there is so much. Aside from 

 the unfavorable physical environmental conditions which make for 

 few plants, there are also biotic environmental elements which are 

 relatively very destructive. Thus the region has supported and now 

 supports an aboriginal population which depends wholly on natural 

 products, animal and vegetable, for its living; and relatively recently 

 the white inhabitants have drawn heavily on every useful native plant. 

 Herbivorous animals of many kinds have also made destructive 

 inroads on the vegetation. Just how all of these biotic factors have 

 affected the flora as a whole will, of course, never be known, but that 

 they are, and long have been, of great importance in many ways can 

 not be seriously questioned. 



VEGETATION OF THE PLAINS. 



The vegetation of the plains was observed in four separate localities 

 on the upper and on the lower plains. So far as these situations are 

 concerned the perennial vegetation was found to be very meager indeed, 

 but there were a few annuals which had sprung up following a small 

 rain of the week preceding my visit. Both classes of vegetation, how- 

 ever, were for the most part restricted in distribution to the small and 

 slight depressions on the plains or to the diminutive drainage channels 

 frequently associated with them. Taken as a whole, aside from such 

 relatively favorable situations as above mentioned, the plains gave 

 little suggestion of plant life. Among the annuals were found Bra- 

 chycome ciliaris and Senecio gregorii, and among the perennials Bassia 

 lanicuspis(t) , which occurred very sparingly, and species of Eremo- 

 phila. The Eremophilas were the most striking and interesting of the 

 perennials. Of these, Eremophila freelingii (plate 2, A and B; plate SB) 

 appeared to be most numerous and was found on both plains. Plate 

 2s shows a typical example of the species in place on the upper plain. 

 It is a much-branched shrub about a meter in height and bears dull- 

 green leaves, narrowly oblong in form, mostly at the end of the 

 branches. The species is fairly rare on the plains, but in and along 

 the drainage channels the population is more abundant and the indi- 

 viduals of a larger size than on the plains proper. In addition to the 

 species referred to, E. lalrobei (plate 3c) has a distribution about like 

 that of E. freelingii, but is possibly not so abundant. In a wash at the 



