karwinskia humboldtiana

from The Collaborative International Dictionary of English v.0.48

Coyotillo \Co`yo*til"lo\, n. [Mex. Sp. dim. See {Coyote}.]
   A low rhamnaceous shrub ({Karwinskia humboldtiana}) of the
   southwestern United States and Mexico. Its berries are said
   to be poisonous to the coyote.
   [Webster 1913 Suppl.]