292 A. A. HAMILTON. 



[In "Shoreline Studies at Botany Bay," 1 E. O. Andrews, 

 b.a., f.g.s., lias demonstrated the capabilities of the Spinifex 

 as a sandbinder, in a diagram p. 169, depicting a " Terrace 

 of accumulation," at Lady Robinson's Beach.] 



On the beaches which it has specially favoured, the 

 trailing stems of this dioecious grass, (the best of our indi- 

 genous sandbinders), creep out from the plateau above, and 

 invest the steep unstable slope to its base, frequently 

 intruding on the strand below. Its flexible stems, which 

 root at every joint, roll elastically from side to side under 

 the pressure of the wind, permitting the moving sand to 

 accumulate beneath them, and bestriding the drift to hold 

 it in position.' The stems are assisted in the work of build- 

 ing and retaining the embankment, by the upright tufts of 

 leaves, which rise from the joints above the roots, around 1 

 which the sand forms miniature mounds, the leaf tufts 

 working upwards as the sand rises. 



The Spinifex is eminently adapted to contend with the 

 adverse conditions inseparable from a strand environment. 

 Its stems are succulent, and together with the leaves are 

 clothed with a shaggy vestiture, the latter are involute in 

 form, and fibrous in texture, a series of characters which 

 provide a maximum of resistance to the attack of the sharp- 

 edged storm-driven sand grains, the desiccating effects of 

 the superficially heated sand, and. the presence of an undue 

 quantity of sodium chloride in the soil. 



To its colleague, Festnca littoralis, is allotted the pioneer 

 work of embankment building and restoration. When 

 operating in a frontal position, the Fescue forms isolated 

 tufts on the beach at the base of the embankment, occupy- 

 ing any vantage points presented by the buttressing sand- 

 ridges at its base. Dotted here and there on the otherwise 

 bare surface, each tuft forms a mound from the sand caught 



1 This Journal, l, p. 165 (1916). 



