I don't often get excited about weeds but some of them are quite attractive. This one was found recently and it reminded me of one I'd found years ago that I thought might be a miniature white morning glory and wondered if there was such a thing. It's taken me a while to find the old, out of focus shot I took back then to compare them. I think they're a match as you can just see the inside pink stamen on the one below. The tiny flowers were only about 2 to 3 cm across.
Unfortunately, I only took the one hasty shot of it back then and when I returned to do a better job, it had been mown over and never grew back which was the reason for my "excitement" to find it again elsewhere. I may have answered my own question because when I searched for white morning glory, I came across something called Ipomoea obscura or small white morning glory, however, none of the images (and there were many, many of them) showed that dark pink stamen. Then I found reference to Ipomoea lacunosa here and it looks exactly like these flowers but the gardener was asking What's this? and I didn't find a reply.
This is a photo of a white morning glory we found in Arrow Town in NZ last year and the flowers are at least 8 or 9 cm across.