BY A. A. HAMILTON. 495 



moisture. Another xerophytie shrub with a coastal range in 

 southern New South Wales, Victoria and Tasmania, occasional 

 in this habitat, is the heath-leaved Kunzea corifolia Reichb., but 

 its preference for a more brightly illuminated station is shown 

 by its greater frequency and larger colony in an open situation. 

 The Kunzea maintains its association with the Bursaria and 

 Melaleuca nodosa throughout their several habitats and reaches 

 its maximum communal growth on the shale flats. 



In a Casuarina forest at Cook's River on a clayey alluvium 

 flat on the western side of the lllawarra Road, the trees on the 

 landward side have been felled, the undergrowth cleared, and 

 the land laid down in pasture. The soil nearest the river is 

 too salt for the Couch and Buffalo grasses, of which the sward 

 is composed, and a broad band of Sporobolus virginicus is estab- 

 lished along the river margin, extending inland until the drier 

 conditions and reduced soil salinity become sufficiently favour- 

 able to the pasture grasses to enable them to resist further en- 

 croachment. The original vegetation is reappearing, and already 

 some of the shrubby species have recaptured small areas and 

 are driving back the introduced vegetation, especially on the 

 liver front where the trees were not disturbed. In the habitat 

 subject to the clearing operations several aliens have established 

 colonies, temporarily replacing the natural undergrowth. The 

 Lantana, Lantana camara L., an introduction from South 

 America, whose usefulness as a producer of humus on large 

 areas of unoccupied land in Northern New South Wales and 

 Queensland has been somewhat dubiously championed, has here 

 invaded the forest with a weak growth. An aggressive coloniser 

 in poor but well-drained land, it is unable in this swampy soil 

 to form its customary thicket, breaking up into small clumps 

 or individual bushes as it advances towards the river, and offer- 

 ing little resistance to the oncoming shrubby indigenous vegeta- 

 tion. The Lantana is indebted to birds for its distribution, its 

 fleshy fruits affording them a tempting bait. 



The Poke-weed of North America, Phytolacca octandra L., a 

 succulent herbaceous perennial with broad mesophytic leaves, 

 which has a wide range as a ruderal weed in most, tropical and 

 subtropical regions, has established a colony on the flank of the 

 Lantana. The factors of shade and moisture obtaining in the 

 habitat favour the development of the Poke-weed and it is not 

 detrimentally affected by soil salinity, but its soft yielding frame 



