230 A. G. HAMILTON. 
as regards fertilisation, but most introduced species are from cool 
temperate regions, and so the Australian species being warm - 
temperate, are able to hold their own. The dying out of some 
Australian grasses is attributable to over stocking and close feed- 
ing and not to competition. 
In considering the introduction of weeds in Australia there is 
a great difficulty, viz., that it is hard in some cases to say whether 
certain plants are indigenous or alien. It is considered a safe 
rule to take all plants common in the Colony in Robert Brown’s 
time as truly indigenous, but as Brown only collected in the 
neighbourhood of Port Jackson, that course leaves some difficulty 
still. On this subject, Baron von Mueller says in the preface to 
his “Census of Australian Plants,” (1st Edit. 1882)—‘ The lines 
of demarcation between truly indigenous and recently immigrated 
can no longer in all cases be drawn with precision; but whereas 
Alchemilla vulgaris, and Veronica serpillifolia were found along 
with several European Carices in untrodden parts of the Australian 
Alps during the author’s earliest explorations, Alchemilla arvensis 
and Veronica peregrina were at first only noticed near settlements. 
The occurrence of Arabis glabra, Geum umbrosum, Agrimonia 
eupatoria, Hupatorium cannabinum, Carpesium cernuum, and some 
others will readily be disputed as indigenous and some questions 
concerning the nativity of various of our plants will probably 
remain for ever involved in doubts.” As will be seen from this, 
the origin of some plants will and must remain more or less a 
matter of personal opinion. And on referring to lists of plants 
of the various colonies it will be found that their authors differ 
in their placing of these doubtful plants. If we critically examine 
the Census of New South Wales plants by Mr. C. Moore, of 
Queensland plants by Mr. F. M. Bailey, of Victorian by Baron 
von Mueller, and of New South Wales by Dr. Woolls, we shall 
find abundant evidence of diversity of views in this respect. But 
very many weeds present no difficulty at all, although the record 
of their plentiful occurrence in very early days may well surprise 
us. The Rev. J. E. Tenison-Woodst remarks that Leichhardt 
+ Proc. Linn. Soc. of N.S. Wales, Vol. tv., p. 133. 
