First line in the national symbol? (7)
I believe the answer is:
thistle
'national symbol?' is the definition.
'thistle' can be an answer for 'symbol?' (I have seen 'symbol of Scotland' mean 'thistle' so perhaps 'symbol' could also mean 'thistle'). I'm not sure about the 'national' bit.
'first line in the' is the wordplay.
'first' becomes 'ist'.
'line' becomes 'l'.
'in' indicates putting letters inside.
'ist'+'l'='istl'
'istl' put inside 'the' is 'THISTLE'.
Can you help me to learn more?
(Other definitions for thistle that I've seen before include "that blows down when it's windy" , "...Partick" , "Scotland's flower" , "Lithest kind of prickly plant" , "Scottish national emblem" .)