482 ECOLOGICAL STUDY OF SALTMARSH VEGETATION. 



" In the neighbourhood of one lagoon . . . only one small 

 tuft of J. maritimus was collected. This, perhaps, may be ac- 

 counted for by the fact that there are no mud-flats, the soil 

 being of a rather sandy nature." The choice of a muddy rather 

 than a sandy station is characteristic of this Juncus in the Port 

 Jackson district also. 



At Cook's River Juncus pallidus R. Br., a species endemic 

 within the Commonwealth, has established its tufts — slightly 

 taller and stouter- — among those of J. maritimus var., on the drier 

 parts of the marsh plain, but its dominance on the margin of a 

 slightly brackish jdooI — a station into which J. maritimus cannot 

 enter — demonstrates its preference for the less saline habitat. 

 J. maritimus extends from the tide-flooded zone to the boundary 

 of the fluvial station, invading the plain en route where the 

 soil is sufficiently saturated to permit its growth, Cladium 

 junceum declining to accompany it beyond the tidal zone. In its 

 passage across the salt plain, J. maritimus has again discarded 

 its banded formation, the dry conditions causing it to separate 

 into small patches or isolated tufts. [At Swansea, Lake Mau- 

 quarie, hundreds of acres of the marshes are covered with a 

 lax growth of this rush, the individual tufts remaining sufficiently 

 distinct to be non-competitive.] The sequence of the rushes in 

 the ascent of the marsh banks is continued by J. effusus L., a 

 cosmopolitan species, and followed on a higher level by the 

 Australian J. polyanthemus, a slender stemmed form separated 

 from J. effusus by Fr. Buchenau. Of the seeds of J. maritimm 

 var., J. pallidus, J. effusus, and J. polyanthemus, none have more 

 than 24 hours' flotation. The seeds of each of these species 

 emitted a slight coating of mucus when immersed. The position 

 on the margin of the marsh plain, which, owing to its infrequent 

 submergence has become prohibitive to Cladium junceum, is 

 occupied by the Salt-grass, Sporobolus virginicus Humb. & 

 Kunth., a creeping perennial represented in most warm regions, 

 which develops a lax growth, 1--3 inches high, on the verge of 

 the plain, its sward rising and becoming more compact and 

 rigid as it extends inland. In occasional depressions where 

 seepage from the marsh banks has collected, the Coast Couch, 

 Zoysia pungens Willd., also a salt-loving grass, but less halo- 

 phytic than the Salt-grass, forms irregular patches in the sward 

 of the latter, but on the saline plain ranges behind it in in- 

 terrupted bands. The Zoysia is also of perennial duration and 



