Tubers Amy's mashed (4)

I believe the answer is:

yams

'tubers' is the definition.
(yam is a kind of tuber)

'amy's mashed' is the wordplay.
'mashed' indicates an anagram.
'amys' is an anagram of 'YAMS'.

(Other definitions for yams that I've seen before include "vegetables" , "Sweet potatoes" , "Roots" , "Edible tubers from the tropics" .)

I've seen this clue in the Evening Standard.

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