162 J. H. MAIDE . 



The classification of the exudations from some of the species is 

 only intended to be provisional. In the absence of some of the 

 products which I have had no opportunity of examining, I am 

 unable to say, for instance, whether some of them should be 

 grouped as "gums," or as "gum-resins." 



The list of exudations is fairly long, and some of the papers in 

 the bibliography give reference to species not separately enumer- 

 ated. Nevertheless it will be observed that our knowledge of 

 Australian vegetable exudations is only superficial, and if residents 

 in the country will systematically collect all exudations (accom- 

 panied by flowering or fruiting twigs or other botanical evidence), 

 we shall soon be in a position to present further work on this 

 interesting group of substances. A drawback to the collection 

 arises from the fact that the exudation of many of the gums etc. 

 is erratic and accidental, and in our sparsely populated country 

 the gums are often washed away by rain, and the resins often 

 disappear by fire and removal by bees etc., and so escape the 

 attention of the collector. 



From the time of Governor Phillip our vegetable exudations 

 have been fitfully sent to Europe, but as a general rule they were 

 sent home as curiosities, were not collected in sufficient quantity 

 for chemical examination, and no botanical data nor information 

 as to locality and quantity available accompanied the specimens. 

 Following is an instance in point: — "I sent to England specimens 

 of five different gums, in order that they might be examined. 

 These consist of an elastic gum, closely resembling India-rubber ; 

 gum tragacanth; another gum yielded by a sort of Capparis 

 (Adansonia) and which I believe to be hitherto unknown ; and 

 two kinds of gum-resin." 1 



Many Natural Orders yield both gums and resins (or gum-resins). 

 The following are what may be termed gum-yielding Orders, but 

 they exceptionally yield resins : — Pittosporese (Pillosporum); 

 Tiutacese; Meliacese (Cedrela etc.); Sapindacese (Dodoncea); 



1 Journ. of Two Exped., Grey, p. 275. 



