Urquhart. — On natural Spread of Eucalyptus in Karaka District. 383 



Art. XXXVIII. — On the natural Spread of the Eucalyptus in the Karaka 

 District. By A. T. Urquhart. 

 [Read before the Auckland Institute, 11th September, 1883.] 

 Mr. Wallace in summing up his interesting chapter on "The Flora of New 

 Zealand : its affinities and probable origin " (Island Life), points out the 

 remarkable fact that compared with the European, few Australian plants 

 have succeeded in establishing themselves in New Zealand, but it must 

 be borne in mind that there has been a continued stream of imported seed 

 from Europe, affording repeated opportunities for the introduction and 

 establishment of the naturalized plants. 



As nearly all the species which are identical and peculiar to New Zealand 

 and Australia, are either temperate or alpine forms, Mr. Wallace fairly con- 

 cludes that there has been an interchange of species in comparatively recent 

 times. 



In accounting for the absence of such characteristic Australian genera 

 as Eucalyptus, Acacia, Hakea, etc., he says : — " In this particular case, how- 

 ever, we have some very remarkable evidence of their non-adaptation." 

 The evidence of their non-adaptability to spread and run wild in New Zea- 

 land, consisted in there being no record of the fact. . I need hardly point out 

 how local causes — not always apparent — influence the natural spread of 

 most plants ; even the hardy XJlex europmus is not exempt. In my own 

 district, although there are some old-established hedges, I have only 

 observed two self-sown seedlings of Hakea acicularis ; yet Mr. T. F. Cheese- 

 man, F.L.S., says that it " has established itself over several miles of open 

 manuka country at the foot of the Waitakerei ranges, and is increasing fast."* 

 In regard to the Acacias, several species readily establish themselves in 

 most districts ; the allied Albizzia lophantha competes successfully against, 

 and in time destroys, almost the strongest vegetation met with in open 

 country. 



To have hastily placed on record the apparent naturalization of so im- 

 portant a genus as the Eucalyptus, would have been an error ; however, now 

 that its adaptability to spread naturally is fairly established, the fact is worth 

 recording. In pastures, or lands where the native vegetation has been 

 almost entirely destroyed, the gum spreads freely ; on a neighbouring farm, 

 where they have not been checked, there are about 5,000 self-sown plants 

 from a few inches to 15 or more feet in height — scattered more or less 

 about ; the largest of the dense patches — i acre — contains over 300 young 

 trees. 



* Trans. N,Z. Inst., vol. xv., p. 291, 



