Caitlyn Jenner -- Swingin' at the Golf Course (PHOTO)

Caitlyn Jenner eschewed the reality cameras and any sort of glitz or glamour to practice her swing Monday ... at a plain old public golf course.

Jenner showed up at the Westlake Golf Course around noon and stayed for an hour. We're told she mostly kept to herself and worked on her short game and practiced off the tee at the driving range.

We're told Caitlyn -- who was dressed very casually -- was pulling clubs from a golf bag with "Bruce Jenner" emblazoned on it.

Caitlyn, not surprisingly, was cranking the ball farther than any of the other players ... men and women.

When Caitlyn decides to get serious again, she'll have to re-register her handicap with the USGA as a woman. Bruce played at a very high skill level and Caitlyn will probably improve her handicap because of her gender.