Synonym for the grape variety Grüner Barthainer; see there.
The white grape variety comes from Austria or Croatia (or former Austro-Hungary). In the VIVC catalogue the three varieties (possibly varieties) Blue Barthainer, Green Barthainer and White Barthainer are listed with partly identical synonyms:
The glossary is a monumental achievement and one of the most important contributions to wine knowledge. Of all the encyclopaedias I use on the subject of wine, it is by far the most important. That was the case ten years ago and it hasn't changed since.
Andreas Essl
Autor, Modena