84 
E. M. Watson. 
changes in climate, soil and cultivation. To these must he added the problems 
associated with the occurrence of physiological forms, or variants, of an 
individual species. 
The term physiological form is applied to morphologically indistin- 
guishable plants which are known to exhibit constant differences in their 
chemical composition, which differentiate sharply between them. Many such 
examples are known in the Australian flora, particularly amongst the oil- 
bearing plants examined by Baker and Smith, formerly economic botanist 
and economist chemist respectively of the Sydney Technological Museum, 
and by Penfold, the present curator and economic chemist of the same 
institution. Physiological forms occur in Melaleuca uncinata R. Br. (p. 86) r 
Eucalyptus campaspe S. Moore and possibly in Dnboisia Hopwoodii (F. 
Muell.) F. Muell. (p. 94). 
The importance of the occurrence of such variants lies in the facts that, 
firstly, essential though it is in any phytochemical work, correct botanical 
identification does not necessarily tell the full story of the chemical com- 
position of a plant; secondly, the results of the chemical examination of a 
plant cannot necessarily be applied to an apparently identical plant growing 
in other districts, regions or countries; and thirdly, the existence of variants 
may be of considerable importance if commercial exploitation of a plant is 
to be undertaken. 
Provided allowance is made for the possible existence of physiological 
forms and for variations due to climate, soil and cultivation, a knowledge 
of the flora of botanically related countries is of value in any phytochemical 
problem. While, at the present time, it may not be possible to explain the 
origin of the Australian flora, it is apparent that certain elements of it have 
originated in pre-existing floras which have become widely distributed (1). 
Firstly, there is an element of southern derivation, either antarctic or sub- 
antarctic, which is shared with New Zealand, South America and South 
Africa. Secondly, there is a paleotropic element which, originating in Asia, 
has migrated not only to Australia through India, Malaya and the East 
Indies, but has also travelled down the east coast of Africa. We may 
therefore look to the floras of the countries surrounding the Indian Ocean, 
of Melanesia and New Zealand and of South America for information and 
suggestions concerning many of our own plants. To these two elements 
must be added a third, an Australian element, which is most richly developed 
in the stable environment of South Western Australia. 
Much information concerning the chemistry of many indigenous and 
some introduced plants in this State is contained in scientific publications 
of South Africa and India and there is also a wealth of suggestion in the 
folk-lore of the native races of these two countries and of the natives of 
East Africa as well. In the Eastern States of Australia, the chemical 
investigation of plants is being pursued in many institutions and the accu- 
mulation of knowledge of the practices of the aborigines normally proceeds 
with reasonable speed. It is regrettable that in Western Australia so little 
chemical work has been done up to the present, not only oh the elements 
of our flora which are common to other countries, but perhaps more especi- 
ally on those plants which are almost restricted to this part of the world. 
It is also unfortunate that there does not appear to have been any sustained 
effort made to build up a knowledge of the foods, medicinal substances, etc., 
which are used by our own native tribes in the different parts of the State. 
