The Queensland Naturalist September, 1939 
66 
Hyparrhenia , with beneficial results. At the gardens of 
the Acclimatisation Society at Lawnton (Petrie Series and 
Greenstones) an experimental artificial pasture of Per- 
ennial Rye Grass (Lolium perennc) and various clovers has 
been laid down, but though only a few years old, and 
with every attention afforded it, the Perennial Rye is being 
rapidly replaced by other grasses. 
SUMMARY. 
The area considered has a sub-tropical climate 
characterised by summer heat and winter drought. Three 
distinct geological formations occur, namely, Greenstone 
Series, Bunya Phyllites Series and Petrie Series. Asso- 
ciated with the variation of geological characters there is 
a variation in topography and soil types. It was found 
that vegetation was correlated with topographical features 
and these again with geological features. The vegetation 
climax is chiefly open forest, but owing to settlement park- 
land and grassland pseudo-climaxes are the rule. 
The climax grass community on the higher Green- 
stone area is unknown, but Cymbopogon refraetus and 
Digitaria spp. were probably common. 
On the Bunya Phyllites the climax is an ArundineUa 
nepalensis — Aristida spp. — E remoclil oa bimacidta associa- 
tion. 
On the Petrie Series there are three distinct associa- 
tions. On the higher ground the climax is a Cymbopogon 
refract us — Digitaria spp. — Ereniochloa bimaculata associa- 
tion. On the lower ground to the east it is an Aristida 
spp. — Panic mu effusum association. In the extreme east 
Sait Meadow dominated by Sporobolus virginicus var. 
minor occurs. 
Various modifications of these climax types are in- 
duced by natural features, namely: — 
Tea-tree swamps with Ilemarthria compressa as the 
grass indicator and ArundineUa nepalensis , Paspalum 
orbicular e, Sacciolepis indiea and Iscliaemum oust rale as 
associated species. 
Stream banks with shade-demanding species, 
Ottochloa gracillima being the indicator. 
Low-lying damp, but not swampy places with Sporo- 
bolus diander as the indicator species. 
The present pseudo-climax vegetation is dominated by 
Digitaria didactyla associated with Bothriochloa decipiens 
on the higher ground and Paspalum dilatation on the lower 
damp places. In the very damp (not wet ) places Paspalum 
