Reinstatement of Eriostemon banksii (Rutaceae), with a report on the composition of leaf essential oils in E. banksii and E. australasius s. str.

Abstract

Eriostemon banksii A. Cunn. ex Endl., currently recognised as a subspecies of E. australasius Pers., is reinstated at specific level. Characters that distinguish it from E. australasius include: distinctly 5-nerved leaves, non-imbricate bracteoles, beaked fruit, anthers that lack a white apiculum and white petals. A preliminary investigation of leaf essential oils in E. banksii and E. australasius is also presented. Extracts of E. banksii contained both cis and trans-methyl-4-isoprenoxycinnamate, which were absent in E. australasius. Extracts of E. banksii contained proportionally more β-elemene (7.2-8.1%), β-caryophyllene (7.7-8.4%) and an unknown sesquiterpene hydrocarbon (12.3-15.1%), and..