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The terms spine, prickle, and thorn have been variously used interchangeably in plant descriptions and cycads are no exception. It is clear from developmental studies and morphology that cycads do not have thorns, but rather have spines and prickles. Spines are present as reduced leaflets in species of Cycas, Dioon, Encephalartos, and Macrozamia, and none of these genera have prickles. In contrast, some species of Zamia and Ceratozamia have prickles, but none have spines. Lepidozamia, Bowenia, and Stangeria have neither spines nor prickles.
Keywords: prickle, spine, thorn