Ground Cover - looks like mini mandevilla?!

I know this is going to be a hard one to identify mainly because I did not have a camera with me on my walk (shame shame) but I came across a beautiful ground cover with a trio of round or fat oval green leaves and the flowers look exactly like the Alice du pont with five petals and the yellow center but they are very small. I would guess that the flowers are approximately 1-3/4 to 2" across and the leaves spring up about 2-1/2" from the dirt. Does anyone have any idea what this might be? I'm in southern California and I've seen this ground cover (if it truly is a ground cover) twice. Next time I'll make sure I have my camera with me.

Thanks,
Nancy

Although the leaves of what I'm suggesting don't match your description, maybe it's Calibrachoa? Ck. the PlantFiles under that name or "Million Bells" there's several pictures of the assorted colors.

Calibrachoa was my first thought too. The other thing I can think of is some sort of Oxalis, there are a couple that have pink flowers and are blooming now. You didn't mention whether it was in sun or shade, but there are some Oxalis that like sun and some that like shade.

Here's a link to Plant Files for the Calibrachoa: http://davesgarden.com/guides/pf/adv_search.php?searcher%5Bcommon%5D=&searcher%5Bfamily%5D=&searcher%5Bgenus%5D=calibrachoa&searcher%5Bspecies%5D=&searcher%5Bcultivar%5D=&searcher%5Bhybridizer%5D=&search_prefs%5Bblank_cultivar%5D=&search_prefs%5Bsort_by%5D=rating&images_prefs=both&Search=Search
And here's Oxalis: http://davesgarden.com/guides/pf/adv_search.php?searcher%5Bcommon%5D=&searcher%5Bfamily%5D=&searcher%5Bgenus%5D=oxalis&searcher%5Bspecies%5D=&searcher%5Bcultivar%5D=&searcher%5Bhybridizer%5D=&search_prefs%5Bblank_cultivar%5D=&search_prefs%5Bsort_by%5D=rating&images_prefs=both&Search=Search

My Oxalis hirta has been blooming its head off lately and I think might fit your description, although it could definitely be another species too http://davesgarden.com/guides/pf/go/64892/

Hi JasperDale and ecrane2,

I just went through my very thick encyclopedia of plants and thought it might be Oxalis and then I saw your posts. I looked at Calibrachoa and don't think it's that but I believe it very well may be the Oxalis Depressa at http://davesgarden.com/guides/pf/showimage/47118/

I'm going to have to go by that house again and take a photo then compare it to the O. Depressa photos to make sure they are one in the same.

Thank you so much - that was pretty incredible of you both to even come up with something based on my flimsy description!

~Nancy