A superficially similar but entirely unrelated flowering plant genus , mare 's tail -LRB- Hippuris -RRB- , is occasionally misidentified and misnamed as `` horsetail '' .

The superficially similar flowering plant , Mare 's tail -LRB- Hippuris vulgaris -RRB- , unrelated to the genus Equisetum , is occasionally misidentified and misnamed as a horsetail .
