The Collaborative International Dictionary of English v.0.48:

Premorse \Pre*morse"\, a. [L. praemorsus, p. p. of praemordere
   to bite off; prae before + mordere to bite.]
   Terminated abruptly, or as it bitten off.
   [1913 Webster]

   Premorse root or Premorse leaves (Bot.), such as have an
      abrupt, ragged, and irregular termination, as if bitten
      off short.
      [1913 Webster]