broomcorn

from WordNet (r) 3.0 (2006)

broomcorn
    n 1: tall grasses grown for the elongated stiff-branched panicle
         used for brooms and brushes [syn: {broomcorn}, {Sorghum
         vulgare technicum}]

from The Collaborative International Dictionary of English v.0.48

broomcorn \broom"corn\, broom corn \broom" corn`\ (Bot.)
   A tall variety of grass ({Sorghum vulgare} technicum), having
   a joined stem, like maize, rising to the height of eight or
   ten feet, and bearing its seeds on a panicle with long stiff
   branches, of which brooms are made.
   [1913 Webster]