30 
and Vitis opaca F. Muell. a native grape with enormous 
tubers sometimes twelve to eighteen inches long which 
can often be seen exposed on the eroded face of the dunes 
at the southern extremity of the island. In one place there 
is a small group of the sand cypresSjCaZ^itris cohimellaris 
F. Muell. 
The species of the more inland dunes persist to the 
tops of the ocean-side dunes but on the seaward slopes 
are gradually replaced by other species characteristic of the 
less stabilised sand. Here Spinifex hirsutus Labill. is the 
most common species but other species often occurring 
commonly are Ipomoea pes-caprae Roth, Eraarostis inter- 
rupta Ream'., Carpohrotus aequilatei’us (Haw.) N.E, 
Brown, Glifcine fahacina I^enth., Zoijsia macrauiha Desv., 
Euphorbia peplus L., Scaevola saiiveole7is R. Br., and 
■Ilibbertia volubilis Andr. ‘Where a low flat expanse of 
sand exists between the dunes and the tidal beach proper 
this area may be thrown into numerous hummocks by the 
fleshy Crucifer Cakile marifima Scop., which builds up 
the sand into a mound sometimes 1 ft. high and up to 4 ft. 
in diameter. 
In some places the Banks'.a forest is replaced by a low 
dry scrub of rain-forest or senii-rain-forest species. Creep- 
ers such as EmiJax australis R.Br., Ilopa anS'tra.lis R.Br., 
(Tcifouoplesium cpmosuni A. Cunn. and Flaqellaria indica 
L. frecpiently scramble over the sand and into low trees, 
and amongst the more common tree species seem to be 
Cupaniopds anacardioides Radik., IlaJfordia kendak Guill., 
Acron!j(dna laeP's Forst., Eugenia smithii Poir., Polyscias 
cJega ns Harms, Alphiton ia excelsa Reissek, Exacarpus 
lafifofia R.Br., Canfhitim coprosnwides F. Muell., Maba 
fasciculosa F. Muell, and Hibiscus tiliaceiis L. 
Ycgeiation of the Southport Sa)id Spit 
The dunes of the Southport sand spit are as yet only 
partially stabilised by an incomplete ground cover and, 
for the most part, trees are entirely lacking. 
From the road between the Jubilee Bridge and the 
31ain Beach surfing area the dunes stretch nortliAvards 
for about 2^ miles as a narrow tongue of land, generally 
about 300 yards wide. Along the eastern or ocean side 
the dunes are raised in a steep generally undulating or 
irregidar rampart while along the river side they are 
fringed for about half their length with mangroves. Tn 
between, the rolling dunes are raised to varying heights 
and along the centre is a series of moist liollows varying 
from a few yards in diameter to perhaps 100 yds. in length. 
The primary coloniser on newly formed dunes is the 
