Thf South Australian Naturallsi. 77 
■\i\ sunlight until near the top. It is here, too, that the man- 
liejvnagum ends and the yellow gum {E. leucoxylon) and the stnngy- 
iilbark (£. obliqua) takes its place. The yellow gum is the domin- 
k ant tree along the top of the ridge where the rocks come to the 
i surface on the higher part. One big tree was was more than four 
ft feet in diameter at breast high and no stringybark of bigger size 
i was seen although they also grow along the ridge top and a 
arc, little way down the side. , i , r 
I!- These two species are associated along almost the whole ot 
h the ridge. There is one place where a pronounced dip occurs^ in 
kc the ridge and it is here that the manna gum is found fornyng 
:r- a colony by itself. There are no exposed rocks in this depression. 
It the soil is finer and deeper and must retain more moisture than 
the higher parts. It is remarkable that this species occurs in 
this way, but it demonstrates clearly its preference for the deeper 
retentive soils. Other gullies have been noted where the manna 
gum comes from the more open, low situations and spreads almost 
’“I to the head to the exclusion of all other species, the stringt'bark 
then takes the place above the manna gum. Going westerly the 
yellow gum and stringybark form the two main trees. Acacia 
pycnantha is sparsely distributed. There Is a remarkable absence 
of shrubs along the ridge although Hibbertia stricta is very plen- 
^'1 tiful but is less than one foot iri height. The ridge falls away 
very abruptly and it is here that the manna gum again dominates 
the tree growth. Ascending this ridge from the side with a 
' southerly aspect there are several noticeable differences In the 
t flora. The manna gum again is the tree of the flat {Long Gully) 
and ascends the s;teep sides of the ridge to near the top. Exocar' 
pus cupressiformis again comes in the lower part and ascends 
half way up the slope. A large shrub, Acrotriche fasciculiflora, is 
' also ah associate here, it is abundant and occurs over the same 
' range as the latter species. The stringybark is situated lower 
down the slope than It is on the other side. Not far from the 
ridge-top the yellow gum again appears and carries itself, with 
the stringybark to the highest parts. 
The association and ecology of this species has been dealt 
with by Adamson and Osborn (1) and our observations are in 
general agreement with theirs. As a general rule the manna 
gum is in association with the stringybark {E, obliqua) and is a 
tree of the higher ranges with a rainfall of 48 inches. The manna 
gum mixes with E. obliqua forests which it penetrates by means 
of gullies where it occurs alone. It has a marked preference 
for gullies where the soil Is finer deeper and richer than in other 
situations. Trees growing in these places can be seen on a train 
"TTpIrans. Roy. Soc. S.ATVol. 48 {\^)7^U\ 
