small white flowers annually.
Opposite leaves let the Peperomia rotundifolia out of consideration; Dischidia is a possibility, but it does not resemble any one I know.
It almost looks like a few plants - Dischidea nummallaria, pilea depressa, or some small leaved hoya but I haven't found a perfect match either.
It would help to have a nice detail picture of the leaf, showing margins, succulence, fuzz or hairs and other details showing including closeup of stem. Also a picture from the top view. Unless someone more familiar recognizes it first.