The South AiLstralian Naturalist. 1^5 



ECOLOGY OF THE COAST OF KANGAROO ISLAND. 



(E.H.L and W.H.) 



Here, where few introduced plants have come in to mar 

 the arrangement worked out through long ages of mutual 

 rivalry and suppression, it is easy to see the way in which the 

 various plants have adapted themselves to particular situa- 

 tions. Different genera occur in fairly regular zones from the 

 water's edge. AVhere the highest tides reach there is a zone 

 composed of dry ''seaweed," mainly seawrack (Zostera). Just 

 out of reach of the highest tides, yet Avithin reach of the blown 

 salt sea spray grows a thick hedge of the ashy salt bush (Atri- 

 plex cinereum), holding its own here where but a bare supply 

 of fresh water reaches its sand-searching roots. We associate 

 the salt bushes with the hot, dry, semi-desert plains of the arid 

 interior. Its presence here reminds us that not heat nor cold, 

 but the supply of moisture is the principal factor in controlling 

 plant life in general. 



Next comes the deep green shapely bushes of Myoporum 

 insulare, ''Boobyalla" as our Victorian friends call it, now 

 crowded with its fruits slowly ripening to a rich purple colour. 

 The berries are reputed poisonous here, though eaten else- 

 where. Here the "Bower spinach" (Tetragonia implexicoma) 

 covers the sandy soil Avith its twining stems, giving place here 

 and there to the pig face, or fig-marigold (Mesembrianthemum 

 trianguhmi). Some fruits are just ripening. Tasting a few 

 we get the impression of a soft pulp Avith a trace of fig and 

 more than a trace of salt ! ShipAvrecked mariners suffering 

 the pangs of hunger may haA^e found it delicious. The islan- 

 ders say that no man need starA^e in the island scrubs. The 

 white stems at the ''heart" of the yacca giA^e a pleasant tasting 

 food, Avhile the craAvling roots of some mallees, Avhen pulled up 

 and cut into lengths, Avill drip quite a quantity of fluid, tasting 

 of "gum," but quite drinkable. The "pig face" Avill giA'e a 

 dessert. (There are no Avild peaches on the island.) 



Next the pig face Ave find an abundance of the coastal 

 berry bushes (Rhagodia) with A^ery small inedible fruits of 

 different colours. 



On this part of the coast the next line of plants is made up 

 of a new arrival, called ' ' fire bush, ' ' from the notion that it 

 springs up after fires, and "sulphur bush," from the yelloAv of 

 its abundant floAvers. It is a Senecio, a member of the Com- 

 posite order. 



