
The IMDb credits for A GIRL’S FOLLY are questionable — I don’t see any evidence for Maurice Tourneur appearing in the film in the role of the film-within-a-film director, or Josef Von Sternberg playing the cameraman (although the actor in AGF *is* short).
But could it be that “Jane Adair,” who plays the heroine’s mom, and who has no other film credits, is the same person as Jean Adair, famed for her murderous maiden aunt role in ARSENIC AND OLD LACE?
I think there’s a faint resemblance, and since Adair was a New York-based vaudevillian, she could have been close enough to Fort Lee, New Jersey, to get cast. She would have been just forty-four, but character players seem to have aged faster in them days, and “Jane” is obviously wearing a peculiar makeup to add the illusion of years to her countenance.
Apparently Jean was also known as Jennet and was born Violet McNaughton, so there’s a history of her name varying. The mother gets her own title card in the film, where it does indeed say “Miss Jane Adair,” so if it’s a mistake, it’s one that has its origins with the film itself.
Both actors seem to have strong nasolabial folds, short, blunt nose or noses, round, dark eyes, short earlobes, slightly squarish chin or chins, thin lips. And I think they both have a slight chip in one front tooth, which tends to almost convince me. The Youtube version is too low-res to be much help in analysing the features, but there are aspects of posture and mannerism which seem to me to be similar. Try the scene at 48.37 if you want to see for yourself.


Jean, circa 1900, and in 1942 filming ARSENIC AND OLD LACE for its eventual 1944 release.
The woman in A GIRL’S FOLLY looks more like the actress in ARSENIC AND OLD LACE etc than her own youthful portraits do, although to be fair, all three of them are pretty distinct from one another.
I have a sad history of misidentifying show people, though. Go ahead, tell me I’m crazy!