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The South Australian Naturalist. 



V 



II. Climatic conditions. 



1. Eainfall, etc. 



2. Evaporation and "wind. 



3. Temperature. 



4. Soil permeability or power of retaining moisture in tlie soil. 



III. Environment. A. Geographic. 



1. Situation or position (coast, plain, hilltop, gullv, river or bank, 

 etc.). 



B. Edaphic (soil). 

 1. Soil composition (sand, loam, clay, slate, quartz, limestone, 

 saline, etc.). 



C. Botanic. 



1. Open formation, "where more than one species of plant grows. 



2. Closed formation, "wliere one species predominates and excludes 



all others. 



Monarto South raihvay station is situated <Sr) miles east from Adelaide 

 on the interstate line, and is 10 miles "west of the River Murray at ^Murray 

 Bridge. 



According to Tate's ''Flora" (Fl. Extr. S.A., p. 204). Monarto is in 

 the "M" District, comprising the plain of the lower ]\[urray River, which 

 is defined on the west by the Adelaide chain (the ^Lount Lofty Range), and 

 exteiuls north-east to the Barrier Range. It is included in the Ereniian or 

 desert region; but it is not typical desert, as its average annual rainfall of 

 14 inches is higher than the other districts (F. C. W. & S.) of that part of 

 the State, Avhich only average 4 to •") inches per year. The following table 

 will illustrate this; Stirling West (Mount Lofty Ranges) is included for 

 comparison : — 



This portion of the ^Murray district benefits in rainfall by the close 

 proximity of the Mount Lofty Range. The heavy winter rains in tlie Mount 

 Lofty hills would extend to ^^lonarto as showers only. The more northerly 

 Eremian areas have a summer rainfall, practically no rain falling in the 

 winter. The medium to scanty rainfall at Monarto affects its flora. 



By way of comparing the Cis-^Iurray plant growth "with that of the 

 hills, we may consider Mt. Lofty, Avith its 4 to ft. of rain per annum, where 

 the St'ringybarks {Eucalyptus oblique, Le Her., and E. capiteliata. Smith) 

 groAv to about 80 feet high ajid 4 feet diameter at the base, and contrast 

 with these the Mallees {Eucahfiifus, spp.), which grow from 10 to .30 feet 

 high, having stems of Avhipstick thickness up to 10 to 12 inches diameter. 

 In this paper I will refer chiefly to the Mallees and their plant associations, 

 as I noted them in August, 1919. 



The Mallees develop stout, stocky bases, which are situated 

 just above or below ground-level. These are the Mallee roots of 

 commerce. They are not easily got out of the ground. When 

 the top growth has been cut down, these swollen bases Avill send up new 

 stems time after time. One of the early problems of the mallee farmer is 

 to keep the land clear of these persistent shoots. So Avell does Nature look 

 after herself that constant shoot destruction, or root grubbing, is necessary 



