384 MANGROVE AND SALTJIARSH VEGETATION NEAR SYDNEY, N.S.W., 



miniature, the history of the association repeats itself. The grroups described 

 above eannot be regarded as separate associations since they are all found 

 mingling freely on old marshes where a fairly uniform surface level has been 

 attained. Thus the term "Zunation" is not used in the same sense as by Yapp 

 (1917, p. 68) in his description of the zoned vegetation of the marshes of the 

 Dovey Estuary in Wales. 



ii. Juncetum Maritimi. 



The inner association of Saltmarsh formation near Sydney is of interest 

 pinee it generally marks the landward boundary. It is often a pure association 

 .of Juiicii.'< mariti)»K-'< Lam., but as Hamilton has shown, further species of Juticuf 

 (1919, pp. 480-482) and Cladium junceum (1919. p. 480) are often found. An 

 interesting feature of this association is the presence in it of the "swamp oak" 

 Casuaiiiia glaitca Sieb. These trees are generally found lining the banks of the 

 marsh on tlie extreme outer limits of the Juncetum but occasionally they occur 

 in local patches of slightly higher level within the association (PI. xxxi.. Photo 

 13). From superficial observation it is apparent that in the saltmarshes around 

 Sydney differences in level, and consequently in drainage, play a large part in 

 the delimitation of the plant associations. This should not form the subject of 

 any generalisation, however, until careful nuul analyses have been made and the 

 results compared for different localities. 



Cabbage Tree Creem, Port Hackixg. 



Cabbage Tree Creek is a small stream entering Port Hacking on its southern 

 side, at a distance of about two miles from the sea. The shore between the 

 mouth of the creek and Port Hacking Point is indented by narrow sandy beaches 

 of vai'ying length {See Text-fig. 1). In a north-easterly direction from the 

 Creek is Cronulla Beach, backed by high mobile sand dunes which extend across 

 to Botany Bay. Tiie entrance to Cabbage Tree Creek is partly l)locked at low 

 tide by sand spits and shoals (Text-tig 11). The larger sand spit projects from 

 the southern shore and resembles in miniature, the sand bars which form a 

 characteristic feature of the lagoons such as Deewhy, Narrabeen, etc., north of 

 Port Jackson (Jose, Taylor and Woolnough, 1911, p. 136). 



The main body of the creek may be divided into two parts, the upper fresh- 

 water to brackish region which runs between gradually ascending sandstone 

 slopes, and a lower, wider, basin-like region in which the water is distinctly 

 saline. The southern shore of this lower portion of the creek is markedly con- 

 cave, and it is here that an extensive tidal marsh has developed. Storm waters 

 entering the creek are sufficient to keep the central channel clear, but since the 

 creek narrows when ncaring the mouth, its load of silt and detritus tends to be 

 deposited upon the concave southern shore. 



When the writer first visited Cabbage Tree Creek in 1916. a short stri]> of 

 sandy beadi abutted on the southern side of the creek entrance. At tlie point 

 where this sandy lieach reached the outlying mangrove at the mouth of the 

 creek, young plants of Avicennia officinalis Linn, and Aegiceras majiiji Gaertn. 

 were already showing signs of burial in drift sand. On the beach itself were 

 recognisable two distinct zones, the strand, witli clumps of Sahola Kali Linn, a 

 little above high tide level, and small transitory hummocks occupied by Senecio 

 Inutus Soland. The second zone, tliat of larger hummocks or embryonic dunes, 

 was diaracterised by an association of such plants a.s Mefiemhnianthemwn 

 aeqttilate-alc Haw., Scaemla suaveolens R. Br., Seiiecio laulufi Soland.. Spinifer 





