14 IIOUN KXI'F.DITION NAHHATIVE. 



le.aves, wliicli is probn,])ly of servico in eliockiiii,' too rapid ovaporation. Tiie 

 ground is not like t-liat wliicli one is accustomed to in iiioister parts ; tussocks of 

 grass, sucli as Sfi)tifex paradoxus, are scattered about, with littler plants of the 

 jed-stemnied and poisonous Eupliorhia Dfui/iriioiidii, or of one or two species of 

 Ptilotus {P. c.xa/ftifi/s and iiii-ain(s), Init they are not crowded together, and you 

 can count the separate plants. It was not at all unusual to see a small patch of 

 ground occupied ciitii'ely l>y a colony of one species of a plant such as Ptilotus. 

 Along by the river ilats the clusters of red fruit of the Darling or Murray Lily* 

 were frequently seen, whilst in the wet season its white flowers are a striking 

 feature along the Stevenson Valley. 



When once they have grown to a certain size, none of the plants growing on 

 tlie Cretaceous table-lands and along the flats bordering the creeks have to 

 compete witii one another for space on which to gi'ovv. The (piestion of which 

 are to survive and which are to die is settled in the main at a very early stage, 

 when they arc seedlings. Directly after the rains have fallen the ground is 

 thickly covered with the bright green of endless seedlings, but it is only those 

 which can reach a certain size and stage of dev<!lopment before the dry season 

 fairly s(!ts in which have any chance of surviving, and at a very early time the 

 weaklings die oflf and the stronger ones are left to grow up witli no competition as 

 between plant and plant, but witli a hard struggle against climatic conditions. 



When we passed through, in the dry season, one of the commonest plants 

 on the ground was a creeping species of Tribulus (7^ tcrrcsfris); its laigo yellow 

 flower is pretty enougli, but its dried and prickly seed cases are more than irrita- 

 ting when you try to camp amongst them, and they seemed to be with us always. 



(.^uite as irritating, though happily not quite so plentiful as the Tribulus, are 

 various species of Bassia. The seed-cases of these have a pretty downy centre, 

 perhaps half an inch in diameter, but around this ai'e a number of vei'y still', 

 sharp-pointed spikes projecting through the soft down. ^^'llat with these and 

 other prickly seeds our camping place was often a bed of thorns, and after 

 selecting a spot, a usual preliminary to opening out our rugs was to sweep the 

 ground with an impromptu l)room of Cassia branches. 



Whilst many plants in the arid and desert regions are protected against too 

 rapid evaporation by having their leaves or leaf-stalks transformed into thin, 

 switch-like structures, others go to the opposite extreme and become thick- 

 leaved and succulent. The uiost connnon of the latter in the district through 



* This is an Ainai'}llid plant— C)('»u»« Jlaccuhim. 



