Tomahawk Hops is part of the CTZ tribe....(Columbus, Tomahawk, Zeus). These three hops varieties are lumped together for a few reasons. At one time, three different varieties were sold to different hops growers. They all marketed them under different names C, T, and Z. It was later discovered, through gas chromatograph, that Columbus was the same variety as Tomahawk. This created a conflict that resulted in a joint venture by the name of HUSE-CEZ, LLC. You can still find Tomahawk and Columbus on the market. Zeus, from the same source but different variety, is so similar in quality and character that it gets associated with these other two.
Please see the Columbus Hops Page for the details on Tomahawk Hops.