BY A. A. HAMILTON. 507 



they ascend the dry hillside. These plants make a close matted 

 growth in the lawn, several species frequently associating, sub- 

 duihg the Couch, and taking possession of small areas during 

 their active growing season. After fruiting, the annuals dis- 

 integrate and the perennials reduce their mat, the Couch resum 

 ing the vacated area. The ruderal grasses are chiefly annuals 

 and range from the meadow at its base to the crown of the slope. 

 They are mostly shallow rooting and scantily tufted and do not 

 interfere to an appreciable extent with the Couch. An excep- 

 tion is provided by the Barley-grass, Hordeum murinum L., 

 which develops a powerful offensive mechanism, its elbow-shaped 

 .stems forcing back and depressing the weaker stems of the 

 Couch and forming a radial patch in the lawn. 



In addition to the introduced grasses several indigenous species 

 of perennial growth are represented on the slopes • and where 

 undisturbed soon re-establish their supremacy. The Kangaroo- 

 grass, Themeda Forskalii Hack. var. imberbis, a tufted grass, 

 maintains a comparatively large colony, its thick tussocky 

 growth smothering the adjoining herbs. The Blady-grass, 

 Imperata arundinacea Cyr., a rhizomatic species, also covers 

 considerable areas, its aggressive underground stems and tall 

 broad aerial flag forming a strong offensive and defensive com- 

 bination. The Blady-grass is frequently associated in this sta- 

 tion with the Bracken Fern, Pteridium aquilinum (L.) Kuhn. 

 The Thistles range throughout the slopes, their strong, rough, 

 fibrous stems defending the colony from aggression by the taller 

 herbs and their heavy basal rosettes suppressing the lower 

 growths. Scirpus nodosus Rottb., a tall slender-stemmed rush 

 common on the shore-line, has a limited representation on the 

 hillside. A series of smaller and weaker herbs in the Couch 

 lawn includes the Common Chick-weed, Stellaria media L., and 

 the Mouse-eared Chick-weed, Cerastium vulgatum L., both intro- 

 dueed weedy annuals, and Cotula australis J. Hook., an Aus- 

 tralian perennial. The members of this group do not form 

 large colonies nor enter into competition with the Couch, their 

 flaccid stems and leaves trailing over the grass which they are 

 not firm enough to displace nor sufficiently close to overshadow. 

 Of the arboreal vegetation on the slopes the White Honey- 

 suckle, Banksia integrifolia L. f. descends into the fluvial zone 

 on the boundary of the Casuarina forest. In their customary 

 habitat on the exposed shore line these trees are compressed into 



