551 



most abundant, together with Nitraria Schoeheri and Zygo- 

 'phyllum fruticulosum, which are more local. 



In some parts, and more especially towards the margin of 

 the Nulla rbor Plain, where very little sand is present in the 

 hollows, Atriple.r vesicarium and other species may occur in 

 some quantity; also C'ratyMylis conoce/phala is abundant. This 

 last is a plant which at first sight bears a most striking 

 resemblance to Kochia sedifolia, a resemblance that is empha- 

 sized when it is growing with Atriplejc spp. fcf. Tate, loc. 

 cit.J. Other perennials in the undergrowth are Rhagodm 

 spinescens, var. deltophylla, and Scaevola spinescefis. 



The annual herbaceous flora is much poorer than that of 

 the ridges, and but few species appear limited to this habitat, 

 e.g., Galotis hispidula, Brachycome pachyptera, and 

 Trichinmm incan^m. Some species, however, are more 

 abundant here, as H elipteriim strictum, Tetragonia expansa, 

 and Pimelea simplex; Stipa, sp., apparently dead, was also 

 locally abundant, and Danthonia penicillata occurred occasion- 

 ally. When the limestone soil came to the surface in a hollow* 

 the annuals of the plain were present. 



''OaW Forest. — Forests of Casuarina lepidopMoia occur 

 to the south of Ooldea. In this vicinity the forests have been 

 much reduced in quantity owing to the utilization of the 

 timber for condensers and other activities associated with the 

 construction of the railway. At present untouched forest is 

 not met till about seven miles are traversed (pi. xxxiv., fig. 2). 



The forest occupies rather flat hollows between sand 

 ridges. The soil, however, is sandy and rather loose all 

 through, even in the centre of the flats. The Casuarinas 

 extend on to the sides of the surrounding ridges but not on to 

 the crests of them, wliich are covered by Acacia linophyUa, 

 A. anev.ra, and .4. Oswaldii, i.e., with a typical sandhill 

 crest community. 



The forest is a very open one, and the trees are often of 

 considerable size. Measurements of some of them showed a 

 diameter of 26 in. at 1 ft. from the ground, and a height 

 of approximately 50 ft. was estimated. When mature the 

 trees have spreading branches, though in the young condi- 

 tion their habit is somewhat strict and pyramidal. * Numerous 

 young trees were coming up in the forest. The "oaks" far 

 overtopped any otiher plants, the other trees present being 

 much smaller; these are Myoporiim platycarpum and mallees 

 (E. oleosa, E. sp. ajfln. oleosa, E. leptophylla). The 

 latter occur on the slopes and ridges, and may reach a height 

 as great as Myoporum, i.e., 20 ft. to 30 ft." Below, and 

 especially between the trees which nowhere form a continuous 



