Several species are superficially similar, but close inspection (and attention to habitat) will usually rule them out fairly easily. A selection is given below.
Odontoschisma denudatum
Matchstick Flapwort
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Biantheridion undulifolium
Marsh Flapwort
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Syzygiella autumnalis
Autumn Flapwort
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Nardia scalaris
Ladder Flapwort
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Solenostoma gracillimum
Crenulated Flapwort
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