100 REPORTS ON THE STATE OF SCIENCE.— 1915. 



the species; thus the amount found in E. pilularis from five widely 

 distributed localities ranged between 0"2 and 0'26 per cent. ; E. regnans 

 gave 0'27 per cent. ; E. Delegatensis 0"3 per cent. ; E. ohliqua 0'22 per 

 cent. 



The mean results obtained in the case of these four species show 

 that the manganese present in their timber represents only one part in 

 about one million parts of anhydrous wood ; in five species of ' Iron- 

 barks,' it is one paii in 60,000 parts (3). Again in the case of this 

 group, whatever the variation in the percentage amount of ash in the 

 timber of the several species of the group, the ratio of Mn to the other 

 inorganic constituents is remarkably uniform ; the following are results 

 obtained with the five principal ' Ironbarks ' : — • 



Per cent, of ash. Per cent, of Mn in ash. 



E. paniculata 0-47 140 



E. siderophloia 0-17 1'25 



E. melanopMoia .... 0-172 1-50 



E. sideroxylon 0-072 1-15 



E. crebra 006 1-50 



The indications these ash results afford is that E. crebra and to a 

 .esser extent E. sideroxylon would be found growing naturally on soils 

 more siliceous than that consonant with the other species of ' Iron- 

 barks ' : this is fairly borne out by results. [The exudations or kinos 

 of the big Australian Eucalypts, previously mentioned, are all similar, 

 their tannins giving a violet colouration with ferric chloride. They all 

 gelatinise readily under suitable conditions and contain neither Aroma- 

 dendrin nor Eudesmin nor any other crystallisable substance.] 



There are considerable differences in the general character of other 

 mineral constituents of the several groups of Eucalypts as well as in 

 the amount of mineral matter stored but there is an approximate 

 relative constancy in the amounts of certain elements required by the 

 members of the several groups. Magnesium is a pronounced constituent 

 in the ashes of species belonging to some groups, whilst calcium pre- 

 dominates in those of others. Eepresentative species of the three large 

 groups, the ' Boxes,' the ' Ironbarks ' and the ' Ashes,' show this fact 

 somewhat clearly ; the results in each case with members of the same 

 groups agree closely. 



' Boxes.' E. hemiphloia and E. cdbens : — 



Mean percentage in ash. 

 CaO 51-31 

 MgO 213 



' Ironbarks.' E. siderophloia and E. paniculata : — 



Mean percentage in ash. 

 CaO 29-63 

 MgO 6-92 



' Ashes.' E. Delegatensis and E. regnans : — 



Mean percentage in ash. 

 CaO 1611 

 MgO 21-76 



In a large number of the species in which calcium is the pronounced 

 mineral constituent, oxalic acid is a characteristic piX)duct of metabolism; 



