Shelter king and Welsh emblem (4)
I believe the answer is:
leek
'welsh emblem' is the definition.
(I've seen this before)
'shelter king' is the wordplay.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'king' becomes 'k' (abbreviation for king in chess).
'lee'+'k'='LEEK'
'and' is the link.
(Other definitions for leek that I've seen before include "English town" , "Cylindrical vegetable" , "Welsh national symbol" , "National emblem of Wales." , "Eat the vegetable and keel over" .)