Mudlark! I love that parody of yours. Thanks for making me smile [the threads can get a leetle wee bit dire sometimes...] anyway: I figured out a long while back [and John Leeder of the Can Soc for Mus. Trad agreed, quoting Alan Lomax who preceded my insight] that the song that gave the word was "Green Grow the Laurels", which, if you think about it, is a) nearer in time to the use of the word, b) stressed correctly to produce GREENgo [instead of GREEN GO, evenly stressed].