‘Ilima (Sida fallax) is an indigenous plant that has different forms. It can be a groundcover or a shrub and it can have different colored flowers. The top two photo show the shrub form, while the bottom two are of the groundcover.
I often see this groundcover in the same areas as the Jacquemontia sandwicensis vine.
For more information, go to http://nativeplants.hawaii.edu/plant/view/Sida_fallax.