388 



ON SOME HALOPHYTIC AND NON-HALOPHYTIC PLANT 

 COMMUNITIES IN ARID SOUTH AUSTRALIA. 



By Professor T. G. B. Osborn, D.Sc, and 

 J. G. Wood, B.Sc, Department of Botany, University of Adelaide. 



[Read October 11, 1923.] 



Plates XXXV. and XXXVI. 



The present paper is in the nature of a sequel to one published earlier this 

 year, "On the Zonation of the Vegetation in the Port Wakefield District. ""^^^ 

 Some time must elapse before we can present our observations on the ecology of 

 the arid North-eastern portion of South Australia owing to the size of the area 

 to be examined and the necessity of visiting portions at different seasons of the 

 year. It seems useful, however, to publish some of our data on the halophytic 

 and non-halophytic plant communities in the district since the extent of the 

 former has not been clearly understood. We desire to express our thanks to 

 Lisle G. Johnson, Esq., owner of Dilkera; to Hamilton-Wilcox Limited, owners 

 of Koonamore ; to the Managing Director (A. G. Rymill, Esq.) of the Canowie 

 Pastoral Company, owners of Curnamona ; and to their Managers^ Mr. J. P. 

 Henderson at Koonamore and Mr. L. Boothby at Curnamona. All of these 

 have materially helped us in our investigations by providing accommodation, 

 transport, etc., besides many kindnesses. Without their aid it would have been 

 impossible to undertake the work. 



Introductory. 



In the paper previously referred to we have given an account of the zonation 

 of plant communities when passing from a littoral mangrove formation to a 

 "saltbush" area. We showed that the sequence of communities might be 

 correlated with a progressive decrease in both the soluble salts (whether "total" 

 or "chlorides") and in soil moisture. A deduction was that "saltbush" (a dwarf 

 shrubland of Atriplex spp. ) is a community of arid conditions and is not 

 halophytic. In the present paper we extend our observations to the typical salt- 

 bush country of the pastoralist. and give some of the evidence we have 

 collected as to its essentially arid and non-halophytic nature. Huge areas in 

 South Australia are occupied by a number of plant communities that have this 

 in common — the abundance of dwarf shrubs belonging to genera of the 

 Chenopodiaceae, especially Atriplex and Kochia. The former are popularly 

 termed "saltbushes," because of their appreciably salt taste, the latter "blue- 

 bushes" because of the blue-white colour of the foliage owing to its covering 

 of close cottony or woolly hairs. The abundance of these bushes gives a character 

 to much of the arid and semi-arid portions of South Australia. 



Saltbush has been very inadequately treated in the literature on Australian 

 ecology and even ignored in the vegetation maps that have appeared. The 

 North-east District of South Australia lying east of the Flinders Range from 

 the Murray Basin to Lake Frome is about 25,000 square miles. Saltbushes or 

 bluebushes are the character plants of much of this area, yet the names do not 

 appear on either Diels' map of the vegetation of Australia ^-^ or Griffith Taylor's 

 modification of it<^"^^ published more recently. 



(1) Osborn, T. G. B., and Wood, J. G., Trans. Roy. Soc. S. Austr., xlvii., p. 244, 1923. 



(-) Diels, L., Die Pflanzenwelt von West Australien, Liepzig, 1906. 



(3) Tavlor, Griffith T., Australian Environment, Commonwealth Adv. Counc. Sci. and 

 Indus., Mem. No. 1, p. 27, 1918. 



