BY A. A. HAMILTON". 487 



The Sporobolus sward covering a typical detritus mound on 

 the salt plain at Cook's River is intruded by a lax colony of 

 Lobelia anceps, also an extratropical inhabitant of S. Africa, S. 

 America, and New Zealand. It is a straggling perennial with 

 succulent leaves and stems, and a shortly rhizomatic root system 

 which finds ample room for development in the open network of 

 the debilitated subterranean growth of the Sporobolus. On its 

 margin, a congener, L. debilis L. f., a weak annual indigenous 

 in South Africa, but an alien weed in most temperate countries, 

 has established a compact colony in which the fraternal struggle 

 for space is keenly contested. The individual plants which, 

 under normal conditions are branched and spreading, are so 

 closely packed that their stems are unbranched and leafless 

 almost to the summit which is crowned with a short tuft of 

 leaves. Both species have small flowers, those of L. anceps 

 being light blue and of its congener a dull reddish colour. The 

 small seeds of both species sank within 24 hours. 



Several plants of Cyperus polystachyus Rottb., a perennial 

 sedge confined to Australia, with a range from Port Jackson to 

 Queensland, are scattered through the Sporobolus sward. In 

 the flattened growth of Sporobolus on the detritus mounds, the 

 Cyperus has space in which to develop, but in the erect swards 

 of either Sporobolus or Zoysia on the marsh margin it is 

 speedily suppressed, the taller grasses closing round the short, 

 flaccid, basal leaves of the Cyperus, spreading over them, and 

 depriving them of the light. This sedge occasionally occupies a 

 narrow strip on the margin of the plain between the bands of 

 reeds and the customary lawn on' the marsh banks — a habitat 

 too dry for the reeds and too salt for the grass. A ribbon-like 

 colony of C. polystachyus was noted ranging behind a band of 

 Cladium junceum in this exclusive station on the banks of 

 George's River at Como. 



A small scattered colony of Plantago coronopus L., the onlv 

 rosette-forming species observed in the saltmarsh proper, oc- 

 cupied an elevated position on the mound. This Plantago, an 

 annual in cold climates, is a biennial in the local marshes. It 

 is common in most temperate countries in the northern hemis- 

 phere, chiefly maritime, and probably an introduction into Aus- 

 tralia. This is the only station on the salt plain open to P. 



