WordNet (r) 3.0 (2006):

nailrod
    n 1: tall marsh plant with cylindrical seed heads that explode
         when mature shedding large quantities of down; its long
         flat leaves are used for making mats and chair seats; of
         North America, Europe, Asia and North Africa [syn:
         cat's-tail, bullrush, bulrush, nailrod, reed
         mace, reedmace, Typha latifolia]