Prickly Palm Acrocomia spp. (Arecaceae) endocarps: first records from Irish waters and a review of NW European records

Although at least 34 species of Prickly Palm (Acrocomia) have been described, the genus is currently considered to be represented by only three valid species: A. aculeata, A. hassleri, and A. (Gastrococos) crispa. Acrocomia species are only found in subtropical regions of South and Central America and the Caribbean Islands. Acrocomia diaspores (fruits and endocarps) are naturally dispersed by domestic mammals, wild mammals, bats, birds, reptiles and humans. However, some empty non-viable endocarps inevitably find their way into rivers and eventually float out to sea where they are widely dispersed by oceanic currents and at least some occasionally reach NW European waters from the Caribbean region via the Gulf Stream and North Atlantic Drift. The current review collates all known records of Acrocomia endocarps found stranded in NW Europe, including the first two reported from Irish waters and four previously unpublished UK records. Although the identification of Acrocomia endocarps currently defies efforts to pin them down to species level, at least one the NW European specimens was identified as A. aculeata. Morphometric studies of Acrocomia endocarps, combined with confirmatory genetic analyses, may help to resolve both the identity and provenance of drift endocarps found stranded in maritime regions.