Urquuarr.—On natural Spread of Eucalyptus in Karaka District. 383 
Art. XXXVIIL.—On the natural Spread of the Eucalyptus in the Karaka 
District. By A. T. URQUHART. 
[Read before the Auckland Institute, 17th September, 1883.] 
Mr. WanracE 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 eon- 
eludes 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, ete., 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 Ulea europeus is not exempt. In my own 
district, although there are some old-established hedges, 1 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—1 acre—contains over 300 young 
. trees. ü 
* Trans. N.Z. Inst., vol. xv., p. 291. 
