In G, but with not a single G in the tune?

Here's the Sharp/Karpeles tune in ABC:

  X:0
  T:Black is the Colour
  S:Sharp & Karpeles, 80 English Folk Songs from the Southern Appalachians
  N:they mark an editorial sharp on the last C, which to me sounds just as weird as the original
  M:3/2
  L:1/4
  Q:1/2=60 % my guess - JC
  K:DMix
   A A D/D/| F>F A  F D C|D3
   A A c   | d2  c2 (3edc|A3
   A A c   | d2  c  c e d|A2
  A2 A D   |(F2  A) F D C|D3|]

Its mode is extraordinary (mode 5 of the ascending half of the Japanese in-sen scale!) - it's the only example of that I've ever seen from anywhere and I can't think what to compare it with or imagine where it came from.