204 M. B. WELCH AND A. R. PENFOLD. 



discharge mechanism which is similar to that found in B. 

 pinnata, and corresponds with that observed by Haberlandt 

 (Plant Physiology) in Buta and Pilocarpus. The "cover" is 

 about 0*05 mm. in diameter. Oil glands also occur in the 

 petals and sepals (Plate XIV, fig. 4) and in the cortical 

 tissues of the stems. 



Essential Oil. 



The characteristic and powerful ketonic odour which this 

 plant gives when the leaves are bruised, readily dis- 

 tinguishes it from all other pinnate leaf species of Boronia 

 so far investigated. The examination of the essential oil 

 herein detailed, shows the principal constituent to be the 

 ketone, thujone, doH^O, both <* and fi forms, occurring to 

 the extent of 80 - 90% . It is, therefore, one of the richest 

 bearing thujone oils that have as yet been described. The 

 oil is usually colourless, with slight fluorescence resembling 

 that given by small amounts of the methyl ester of 

 anthranilic acid, and possesses a delightful odour recalling 

 that of "black currants." In fact, a perfect synthetic 

 black currant essence can readily be compounded from it. 

 On account of its characteristic habit of growing in shel- 

 tered gullies and ravines plentifully supplied with moisture, 

 it is naturally somewhat limited in extent of quantity in 

 any particular locality, although probably widely distributed 

 throughout the State (N.S.W*) so far as known, and con- 

 sequently, should a demand for its commercial utilisation 

 arise, it will need to be cultivated. 



Five collections of material, cut as for commercial pur- 

 poses, were made in all from two different localities, a total 

 of 176 lbs. weight being distilled, and with average yield 

 of 0*6%. Three collections were made from Narrabeen, 

 near Sydney, whilst two were obtaiued from Bundanoon 

 (Southern district), about 100 miles from Sydney. Both 

 distillations of plants (total 128 fbs.) collected at Bundanoon 



