Clover (unluckily?) (7)
I believe the answer is:
trefoil
(Other definitions for trefoil that I've seen before include "Three leaved plant like clover and shamrock" , "Plant with leaves in three parts, eg clover" , "Small plant with yellow flowers and three leaves - to rifle (anag)" , "Loftier (anag) -- clover-like plant" , "Three-leaved plant, eg clover" .)