THE FLORAL ODOR OF ARUM-MACULATUM

Non-invasive headspace analyses of the odour produced by inflorescence s of Arum maculatum L. still attached to plants growing wild in southe rn England revealed that the major components were 2-heptanone, indole (each comprising 8-23% of the volatiles) and germacrene B (10-14%). p -Cresol (0.2-6%) was also a notable odorous component amongst the 56 c ompounds present, however, simple amines, reported in previous invasiv e studies, could not he detected. Although the major odorous organ was the spadix appendix, microheadspace analyses revealed that the germac rene B originated entirely within the spathe chamber, probably from th e fertile portion of the spadix. The main pollinator was confirmed as females of Psychoda phalaenoides L. and a comparison of the infloresce nce volatiles with those produced by cow dung, the normal breeding mic rohabitat of the pollinator, identified p-cresol as the major common c omponent.