The Collaborative International Dictionary of English v.0.48:

Tartarean \Tar*ta"re*an\, Tartareous \Tar*ta"re*ous\, a. [L.
   tartareus: cf. F. tartar['e]en.]
   Of or pertaining to Tartarus; hellish.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tartareous \Tar*ta"re*ous\, a. [Cf. 1st Tartarous.]
   1. Consisting of tartar; of the nature of tartar.
      [1913 Webster]

   2. (Bot.) Having the surface rough and crumbling; as, many
      lichens are tartareous.
      [1913 Webster] Tartarian