488 ECOLOGICAL STUDY OF SALTMARSH VEGETATION. 



coronopus, as it requires a permeable soil, usually frequenting 

 a sandy habitat, and is intolerant of the salinity of the plain 

 either in the dry or flooded areas. 



Discussing the dispersal of seeds by Gulls, Guppy (15, p. 421 ) 

 says: . . . " Plantayo coronopus, which grows on the rock 

 ledges where these birds nest. Here the seeds emit mucus and 

 become sticky when wetted, and they would adhere firmly to a 

 bird's plumage when dry." This species was noted by the 

 writer growing on the rock ledges of the ocean escarpment at 

 Coogee (17, p. 339). 



One of the Cudweeds, Gnaphalium purpureum L., a cosmo- 

 politan weed of annual growth was represented on the mounds 

 in small patches. It is more frequent in a moist meadow or 

 the sparse sward of an open forest (Savannah), its lax frame 

 and flaccid mesophytic foliage indicating its anomalous position 

 in the saltmarsh. The xerophytic equipment of the Cudweed 

 consists of a coating of cottony hairs but this provision is in- 

 sufficient for a prolonged resistance to the harsh conditions 

 obtaining in this station, and it frequently collapses before it 

 has reached the flowering stage. The distribution of this wide- 

 spread herb, apart from man, — it is a horticultural and ruderaJ 

 weed — is the work of birds. Though the minute achenes are 

 crowned by a comparatively large parachute-like pappus, the}' 

 are not wind dispersed, as the ring of hairs, united by their 

 bases into a short tube, is detached at maturity and drifts away 

 on the breeze, the small solid seeds falling in the vicinity of the 

 parent plant. The membraneous seed-coat would resist erosion 

 when eaten by birds. The seeds have little flotation, sinking 

 within 24 hours. 



On the dry salt plain at the head of Homebush Bay, the 

 slender Apium leptophylhtm F. v. M., a succulent annual with 

 finely dissected foliage, was sparsely represented among the salt- 

 grasses. This weedy herb is indigenous in tropical Africa and 

 America and has a coastal range throughout Eastern Australia. 

 Though its presence in the saltmarsh and on the seaboard would 

 denote a tolerance of saline conditions, it is not as exclusively 

 halophytic as its coastal congener, A. prostratum Labill.. which, 

 however, does not favour the saltmarsh, owing to its objection to 

 a sour and muddy soil. The structure of A. leptophylhim is 

 largely xerophytic, but it is frequently located in a moist shady 

 sward . 



