Hackmatack

from WordNet (r) 3.0 (2006)

hackmatack
    n 1: poplar of northeastern North America with broad heart-
         shaped leaves [syn: {balsam poplar}, {hackmatack},
         {tacamahac}, {Populus balsamifera}]

from The Collaborative International Dictionary of English v.0.48

Hackmatack \Hack"ma*tack`\ (h[a^]k"m[.a]*t[a^]k`), n. [Of
   American Indian origin.] (Bot.)
   The American larch ({Larix Americana}), a coniferous tree
   with slender deciduous leaves; also, its heavy, close-grained
   timber. Called also {tamarack}.
   [1913 Webster]