November, 1940 
The Queensland Naturalist 
97 
Off the east side of the islands, poorly developed 
communities of the second and third types were observed. 
Several examples of Algae growing epiphytically on others 
were noticed. 
2. TERRESTRIAL VEGETATION. Bird Island 
supports no terrestrial plants, but on Goat Island are to 
be seen the following communities: — 
E. Mangroves. At about half-tide mark, on a rocky 
substrate, a belt of mangroves surrounds Goat Island, 
except at the narrow northern end where it adjoins Bird 
Island. The belt is broad in places, in others narrowed 
down to the width of a single tree, and near the north 
end the belt becomes broken owing to the distance- between 
trees. Avicennia officinalis is by far the commonest tree, 
and on the east is almost the only species. On the west 
and south-west the development is enriched by the com- 
mon occurrence of Aegiceras corniculatum, which forms a 
lower story, an occasional small plant of Bhizopkora 
mucronata showing well the stilt roots so characteristic of 
the species, and a few trees of Bruguiera Rheedii at the 
landward edge. 
None of the mangroves exceeds 20 feet in height, 
while those of the east and south show well the dwarfing 
and shearing effect of the predominant south-east wind. 
The effect of the wind can be seen on most of the trees 
on the island by the pronounced reduction in growth of 
the south-east portion of the canopy. 
F. Between the landward edge of the mangroves and 
high water mark is a sloping sandy beach mostly 5-8 
yards wide (narrower at one or two points only), quite 
bare of vegetation except for a very occasional tree of 
Avicennia. 
G. At spring tide mark there is a distinct tendency 
for the production of a strand flora. Particularly in the 
northern part is a well-developed but narrow zone of 
Sesuvium port ulacastru n i w ith M esem b ry ant hem uni 
aequilaterale. The former occurs at intervals elsewhere 
along the coast, and particularly towards the south-west. 
Towards the north an occasional plant of Suaeda maritima 
occurs. 
H. Immediately behind this Sesuvium zone, and 
mingling with it in places, is a much broader zone of the 
grass Sporobolus virginicus , with Wedelia biflora and 
