BY MARJORIE I. COLLINS. 387 



as Samolus repens and Spergularia rubra had begun to spread over locally 

 elevated patches. 



At the present day there are but few species represented on this saltmarsh 

 in comparison with the marshes of Port Jackson and George's River. 

 The plants recorded are : — 

 1. Salicornietum. 

 Salicornia australis. 

 Samolus repens. 

 Sporobolus virginicus. 

 Suaeda australis. (few isolated plants). 

 Spergularia rubra, (few isolated plants). 

 2. Jdncetum. 



■Juncus maritimujs, with occasional jnitches of CasiMrina glauca. 

 Juncus niaritimus does not occupy tlic landward fringe only, but shows 

 encroachment upon the Salicornietum. Bands of Juncus have traversed the 

 saltmarsh to the outer fringe of mangrove in places (Text-flg. 11; also PL ssxi., 

 Photo 14). 



It is in this invasion by Juncus of Salicornietum perhaps, that we can 

 partly accoiuit for the paucity of species in the latter. It seems likely that 

 the rate of raising of the level of the marsh is gi-eater than that of establish- 

 ment of species. The remarkable diminution in number of plants of Suaeda 

 aikstralis is doubtless owing to unfavourable conditions for establishment of seed- 

 lings. Also the formation of extensive meadow-like areas of Samolus repens 

 (Fl. XXX., Photo 11) within the Salicornietum, is apparently helping to make 

 conditions unfavourable for the establishment of other species on account of 

 its close mat-like growth. 



In this marsli there has been a hurrying over certain developmental pliases, 

 so that it is impossible to recognise any transitory groupings or assocics within 

 the associations. 



Thus, in certain important features, the tidal marsh at Cabbage Tree Creek 

 differs from the typical marshes of Port -Jackson and Botany Bay. Here, 

 owing to special conditions, one plant formation has been imposed upon another, 

 and, within the second formation, one association (.Juncetum) has invade<l and 

 arrested the development of the other (Salicornietum). 



General Discu.s.sion. 



The subsidence of a coastal region of youthful topography and the subse- 

 quent drowning of river valleys, has been, in part, responsible for the com- 

 paratively restricted nature of the tidal marshes in tlie neighbourhood of Sydney. 

 The absence of any large, delta-forming rivers, ha.s resulted in the limitation of 

 saltmarsh to tlie silted bays and creeks found in the arms of drowned river 

 valleys such as Port Jackson, Botany Bay and Port Hacking. These stations 

 are always sheltered from the open sea and consequently the part played by 

 certain Algae in their consolidation is not so important as is the case in certain 

 British saltmarshes (Carey and Oliver, 1018, p. 170). Although the writer 

 has fnade no attempt to deal with the algal vegetation of the saltmarshes near 

 Sydney, it might not be out of place to record the occurrence of species of 

 Cladophora, Viva and Enteromorpha, tlie first of which is apparently not re- 

 presented on the British saltmarshes (Carey and Oliver, 1918, \>. 267). Leaves 

 of the grass-wrack Tiostera, washed up by tides, probably play a more important 

 part in New South Wales in helping to consolidate and in adding organic 

 matter to the m>ul. In the pioneer phases, saltmarsh near Sydney resembles 



