TOPOGRAPHICAL. ECOLOGICAL, AND TAXONOMIC NOTES. 307 



dime formation reappears, and a little further south the 

 shoreline again alters, the bare embankment facing the 

 ocean disclosing the local shale. Two shrubby species 

 occupy prominent positions on its verge, the "Coast Rose- 

 mary," Westrlngla rosmariniformis Sm., and the "Coast 

 Tea-tree." The former is rarely found more" than a few 

 hundred yards inland, and exhibits a preference for the 

 headland rather than the dune. Its associate, on the con- 

 trary, reaches its optimum on the dune, though it occasion- 

 ally forms by no means despicable colonies on the more 

 sheltered parts of the rocky hillside. 



The root system of young plants of the Coast Tea-tree 

 growing on the dune is chiefly lateral, the tap-root in the 

 example exhibited measuring 4} inches, the laterals reach- 

 ing a length of 18 inches. This arrangement is due to the 

 fact that the modicum of humus in the dune soil is super- 

 ficial, the roots spreading in the direction of the food supply. 

 In a comprehensive article on "Sand-drift Problem in New 

 South Wales," 1 the Government Botanist, Mr. J. H. Maiden 

 says of this species, (p. 988), "Let me particularly emphasise 

 the value of Lepbospermum Icevigatum, Nature's special 

 sand-stay for many parts of coastal New South Wales." 



At the southern end of the headland the escarpment 

 descends with a steep grade to Deewhy Beach. Two 

 undershrubs were noted on its slope, Acacia myrtifolia 

 Willd., and Styplielia humifusa Pers., the prostrate Ground 

 Berry, neither of which is found on the frontal dune 

 slopes. The waters of the lagoon behind the beach have 

 overflowed in several places, and formed broad shallow 

 drainage channels across the dune, extending to the strand. 

 In this moist area the sand or mud creeper, Bramia indica 

 Lam., has formed large carpets, connected throughout by 

 its creeping stems. Associated with it is a diminutive 



1 Agric. Gazette N. S. Wales, Vol. xvn, p, 975. 



