Lay down each narcissus initially on tomb (8)
I believe the answer is:
enshrine
'lay down' is the definition.
(eg enshrine in law is to lay down in law)
'each narcissus initially on tomb' is the wordplay.
'initially' says to take the initial letters.
'on' means one lot of letters go next to another.
'tomb' becomes 'shrine' (shrine can mean a tomb or memorial).
The initial letters of 'each narcissus' is 'en'.
'en'+'shrine'='ENSHRINE'
(Other definitions for enshrine that I've seen before include "Preserve as worthy of reverence" , "Preserve and cherish as in holy place" , "Hold sacred - protect" , "Preserve (something) to be cherished" , "Preserve (an idea) so that it will be respected" .)