In another thread the topic of duplicate common names came up.
Golden rain tree, Cassia fistula
Golden rain, Laburnum anagyroides
Goldenrain tree, Koelreuteria paniculata
‘Urchin’ as a common name for both sea urchins and porcupines always makes me smile, personally.
Any favorite (Edited to add: or endlessly irritating) examples of unrelated species with the same common names?