PKOSTANTHERA AND ITS ESSENTIAL OIL. 103 



On a NEW SPECIES of PROSTANTHERA and its 

 ESSENTIAL OIL. 



By R. T. Baker, f.l.s., and H. G. Smith, f.c.s. 



With Plate I. 



[Read before the Royal Society of N. S. Wales, July 3, 1912.] 



Introduction. 

 The genus Prostantliera is endemic to Australia, and com- 

 prises some fifty species, a few new ones having been 

 described in recent years. They form a very distinct 

 group of the natural order Labiatae, and are distinguished 

 in the bush by their aromatic flowers and leaves. 



The presence of oil in their leaves has long been known, 

 and Bosisto, as far back as 1862, distilled oil from P. lasi- 

 anthos and P. rotundifolia. The latter species yielded 0*75 

 per cent, of oil ; the former very much less. No constitu- 

 ent, however, was indicated, and, so far as we are aware, 

 the constituents common to the oils of the Prostantheras 

 have not previously been determined. The isolation of 

 cuminaldehyde is perhaps of some importance for diagnostic 

 purposes, as it does not appear to have been previously 

 isolated from the oil of any member of the Labiatse. Cineol 

 is not uncommon in the oils of the group, and the phenols 

 thymol and carvacrol often occur. 



The Prostantliera, the subject of this paper, was received 

 at the Technological Museum in October 1908, having 

 been forwarded by Mr. B. Howitz of the Imperial Hotel, 

 Singleton. He sent later 20Ibs. of the material for distil- 

 lation. The amount of oil distilled from this was altogether 

 too small for complete investigation, but it was shown to 



