For what it is worth, Calflora indicates that there is only one species of Commelina in California, Commelina benghalensis.
USDA Plants shows another species, Commelina coelestis, but it appears to have an extremely limited distribution. It's also rather unusual looking for a dayflower:
Day Flower (Commelina coelestis)
The wikipedia entry for Commelina benghalensis says it's only been present in California since the 1980's, but you shouldn't worry too much about that. First, it's wikipedia
and, second, plants are commonly present in places for long periods of time before they are officially noted.
