Possible Clues:

• Subject in a stiff examination?
• Body of work for Agatha Christie?
• Additional material in heart -- subject of autopsy
• Chap's rear squeezed into short item of underwear: laugh uncontrollably
• __ flower: foul-smelling rare plant
• Romeo entering small wood causes laugh on stage
• Body of rook found in small wood
• Body of ramblers' leader buried in spinney
• Forget lines
• Dead body of rook in a group of trees