Toss an essayist a flower (7)
I believe the answer is:
lobelia
'a flower' is the definition.
(I've seen this before)
'toss an essayist' is the wordplay.
'toss' becomes 'lob' (I've seen this in another clue).
'an essayist' becomes 'elia' (pseudonym of Charles Lamb).
'lob'+'elia'='LOBELIA'
(Other definitions for lobelia that I've seen before include "Garden plant with five-lobed flowers" , "Lo, I bale out the flower" , "Oilable (anag)" , "Herbaceous plant - boil ale (anag)" , "something flowery" .)