Mainlander's memento (3)
I believe the answer is:
lei
'mainlander's memento' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lei that I've seen before include "Hawaiian ring of flowers" , "ready in Romania" , "Flower arrangements" , "Garland of flowers, may accompany 5 Down" , "Flowers worn round the neck" .)