20 THE TRANSVEESE SECTIONS OF PETIOLES OF EUCALYPTS 



The Anthereal system " has proved the most convenient for easy-working with 

 museum material, so long as it was the mam object to ascertain the name of any 

 species." (Euc. I. " IntrocUiction.") 



There is another system recently propounded which ought to be noticed here, 

 viz., the " Kino system " of Maiden.* It is a chemical check, which he merely offers 

 as a supplement to other systems. 



The three groups at present recognised are : — 



1. Euby group, with ruby-coloured kinos, soluble either in cold water or spirit ; 

 E. macrorrhyncha, obliqjia, and amygdalina, investigated by us, belong to this group. 



2. Gummy group, containing gum, and therefore imperfectly soluble in spirit, 

 but soluble in cold water. E. leucoxylon and saligna belong to this. 



3. Turbid group, soluble in hot water or alcohol, but the solution becomes turbid 

 on cooling. 



With regard to the present system, we consider that it has many advantages and 

 few disadvantages. The Eucalypts being evergreens their leaves are readily obtainable, 

 and where the leaf happens to be sessile the section of the base of the midrib may 

 serve the purpose. The resemblance in habit of many different Eucalypts is often 

 misleading and always confusing, and the basing of characters upon the internal 

 anatomy, which is not so subject to fluctuation as the external, is an advantage. 



Again, the most persistent part of the petiole — the wood — is often sufficient for 

 purposes of discrimination, and it may be used, therefore, for the determination of 

 museum material. 



It has, moreover, this great advantage, that it enables us in doubtful and difficult 

 cases to decide whether the balance of evidence is in favour of specific identity or 

 merely varietal distinction. 



It may be an objection that the above are not naked-eye characters, and that the 

 system is suited rather to the laboratory than the field, but while less minute 

 characters may be used for rough discrimination, the final test for specific distinction 

 must be based upon essential characters that do not always lie upon the surface. 

 Moreover, the internal structure has been hitherto too much neglected by systematists, 

 just as anatomists have in like manner paid too little attention to the characters 

 recognised by the former. If the whole truth is to be expressed by our classification, 

 then all the features, external and internal, must be taken into account. 



* Pharm. Jour. XX., p. 221. 



