THE 
South Australian Naturalist. 
VOL V. ADELAIDE. MAY, 1924. No. 3. 
SANDHILL PLANTS. 
Different species of plants have adapted themselves to 
almost every soil and to practically every variation of climate 
and situation. The botanist calls the study of these relations 
between plants and their surroundings (or environment) Plant 
Ecology. We are making observations in Plant Ecology when 
w'e cross the parklands and notice the different weeds on the 
rises, and contrast them with those growing down in the hol- 
lows. On a bigger scale, we note the great plains covered with 
saltbush and bluebush^ the ranges with their stringybark trees, 
and the creeks with their red gums. The deep, rich soils bear a 
wonderful variety of plants, but even the stoniest part has a 
few plants which have adapted themselves to the hard condi- 
tions of life, with little soil and less water. The sandhills of 
the coast, such as those which occur here and there between 
Brighton and the Outer Harbour, illustrate this adaptation in 
a very marked degree. 
As we walk along the coast we recognise the saltbush, 
with its eharacterivStie grey-green colour and fleshy leaves. We 
associate the saltbush with the drier interior, but here the rain- 
fall is good. Why, then, should it luxuriate here ? The answer 
is found by looking at the make-up of the soil. The soil 
is almost pure sand; under the lens ^xe see it is made up of 
little grains of hard rock quartz along with tiny pieces of 
shells and corals. But compared with the grains in good soil 
the particles of the sand are very large, and the quantity of 
water held is immensely decreased. The water runs through 
quickly, and in a short time the sand is dry between the grains. 
Now, plants gain their moisture from the water held between 
the particles, so that a plant in vsandy soil, no matter how heavy 
me rainfall, is really growing under droughty conditions. 
Hence we see the same families, and even species, of plants 
growing on the seashore as in the arid interior. The saltbush 
has become able to adapt itself to desert conditions and can 
nourish on the sandy shore as well as in the dry interior. 
We may leave the level sands of the shore and climb up 
the sandhills (dunes) tai'ther inland. Wo notice lhat a large 
part of the surface consists of loose sands blown by every wind, 
