544 



connection it may be noted that perennial lierbaceous plants 

 are noticeably rare in tlie Ooldea flora. Another adverse factor 

 is the drying winds which sweep ov^er the plain. Ooldea is. 

 80 miles from the sea, and the intervening conntry is similar 

 waterless plain or sandhill. Even the soutii and south-west 

 winds have their humidity reduced before reaching Ooldea, 

 while any other wind travels considerably further overland 

 before it gets to that place. All winds, but especially those 

 off the deserts that lie north and north-east and north-west, 

 must be regarded as influences operating adversely to the 

 veoretation. 



Previous Work on the Flora. 



The paper of Tate before mentioned includes a list of the 

 flora at the head of the Bight as well as some not-es on the 

 vegetation. The region traversed by him, being near the 

 coast, has a higher rainfall than Ooldea, and also gains con- 

 siderable moisture from sea mists for a distance inland of 

 20 miles. ^8) iSTevertheless, the vegetation seems essentially 

 similar. Tate's '^^ notes on the tlora are valuable, especially 

 noteworthy being the clear distinction that he makes between 

 such halophytes as Arthrocrvemum spp., and xerophytes as 

 Kochia .^edifolia. Saltbushes, Atrijjlex spp., are assigned an 

 intermediate position ; they show considerable salt toleration, 

 but not to the same degree as the truly halophytic shrubby 

 Salicornias. 



The Ooldea region has been studied floristically recently 

 by Black. '10) Cannon visited the district in 1918, and his 

 observatioUvS are included in his recent w^ork on the "Arid 

 Portions of South Australia." No attempt is made^ii* by 

 Cannon to give a complete account of the flora, but the main 

 habitats are studied with reference to some of the most prp^ 

 minent plants occurring there. Cannon distinguishes the 

 Nullarbor Plains, the sandhills, and a transition region 

 between the two ; the dongas and the hollows between the 

 ridges in the sandhills are also indicated as probably dis- 

 tinct. With his account we are in general agreement, except 

 that the characteristic bluebushes and saltbushes of the plains 

 are classed by him as halophytes. With this we disagree. 



(8) Brown, T., loc. cit., p. 147. 



(9) Tate, R., loc. cit., pp. 118-121. 



(10) Black, J. M., Trans. Rov. Soc. S. Austr., xli., pp. 378-390, 

 1917, and xlv., pp. r>.2i, 1921. 



(11) Gannon, W. A.. Plant Habits .and Habitats in the Arid 

 Portions of South Anstraha. Carnecrio Inst, of Washington, Pnbl. 

 No. 808. 1921, pp. 81-89. ^ . 



