500 ECOLOGICAL STUDY OF SALTMARSH VEGETATION. 



also has a tuberous rootstoek, is occasionally associated with the 

 Gladiolus, and they were noted in close proximity in a peaty 

 swamp in Centennial Park. 



The Fox-tail Grass, Polypogon monspeliensis Desf., an im- 

 migrant from the Mediterranean, enters the various herbaceous 

 associations , on the border of the salt plain, the flaccid tufts ac- 

 commodating their growth to the pressure of their hosts by a 

 vertical uplift. In a close sward of Couch or Buffalo this 

 short-lived grass makes a weak growth a few inches high, but 

 in an open formation of Cotula cor onopi folia in the fluvial 

 mud or on the mounds at the base of the Casuarina trunks, it 

 reaches a height of 1J— 2 feet. An Australian Composite, 

 Epaltes australis Less., a fleshy prostrate perennial with dull 

 brown rayless (discoid) flowers, forms a scattered colony on the 

 margins of the depressions in the vicinity of the salt plain. This 

 weedy herb is rarely subjected to competition as it is tolerant 

 of a sour soil and usually occupies a habitat shunned by other 

 herbage. It has established numerous colonies on the ill-drained 

 Wianamatta Shale flats in the Fairfield-Canley Vale district. 

 The achenes of this species sank within 24 hours. 



Jussieua repens L., a cosmopolitan perennial, creeps in the 

 mud or builds up a mass of matted herbage in the shallow pools. 

 When growing on the mud or in shallow water the Jussieua 

 develops breathing roots on the submerged rhizomatic stems in 

 the interstices between the joints from which the true roots 

 emerge. When floating in deej:>er water the plants are fre- 

 quently beset with small bladder-like cavities (vesicles) around 

 the base of the leaves, which are occasionally present in suffi- 

 cient numbers to sustain the stems. Paspalum distichum L., 

 a cosmopolitan grass with a creeping habit, builds up a thick 

 sward in the shallow depressions. Bailey* separates this species 

 into two distinct varieties, normale and littorale. The former 

 he describes as a broad-leaved grass which grows in fresh water 

 and the latter a narrow-leaved form confined to brackish swamps. 

 This distinction was noted locally, the plants growing in fresh 

 water showing a broad lush (mesophytic) flag, and those in 

 the brackish station the tough wiry leaves of the xerophyte. In 

 his Manual of the Grasses of New South Wales, J. H. Maiden 

 gives some interesting ecological references, climatic and edaphic, 



Queensland Flora, vi., 1902, p. 1814. 



