Raphides in palm embryos and their systematic distribution

BACKGROUND AND AIMS: Raphides are ubiquitous in the palms (Arecaceae), where they are found in roots, stems, leaves, flowers and fruits. Their occasional presence in embryos, first noticed over 100 years ago, has gone largely unexamined. METHODS: Embryos from 148 taxa of palms, the largest survey of palm embryos to date, were examined using light microscopy of squashed preparations under non-polarized and crossed polarized light. RESULTS: Raphides were found in embryos of species from the three subfamilies Coryphoideae, Ceroxyloideae and Arecoideae. Raphides were not observed in the embryos of species of Calamoideae or Phytelephantoideae. The remaining subfamily, the monospecific Nypoideae, was not available for study. CONCLUSIONS: Within the Coryphoideae and Ceroxyloideae, embryos with raphides were rare, but within the Arecoideae, they were a common feature of the tribes Areceae and Caryoteae.