Xiphidium caeruleum (Haemodoraceae) flower organs such as carpels, pedicels, petals, and stamens were separately investigated for their phytochemical profile. The stamens appeared to be a rich source of previously undescribed phenylbenzoisoquinolindiones, a group of phenylphenalenone-derived alkaloids, also named aza-phenylphenalenones. Nine previously undescribed compounds with an identical aza-phenylphenalenone core structure but different amino acid-derived side chains at position 2 were isolated and their structures elucidated by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). In addition, some previously reported phenylbenzoisoquinolindiones, phenyl-benzoisochromenones and flavonoids were found in stamens and other parts of the flowers. The specific occurrence of heterocyclic phenylphenalenone-type compounds in X caeruleum suggests these are involved in physiological or ecological processes. (C) 2016 Elsevier Ltd. All rights reserved.