Purslane speedwell

Flowers: Short-stalked flowers in loose racemes on branching stems, open for a short period mid-day. Flowers are tubular, less than 1/8 inch across, with four oval to round petal-like lobes; the upper can be slightly larger and the lower slightly smaller, but often they are all nearly equal in size. Typically white but may have a pinkish cast. Behind the flower and alternating with the petals are 4 green sepals about as long as the petals. At the base of the flower stalk is a leaf-like bract, so it appears the flowers arise from leaf axils. The flowers wilt rather quickly and fall away to be replaced by other flowers the next day.
Leaves and stems: Lower leaves are up to ¾ inch long and 1/3 inch wide, opposite, oblong with a blunt tip, mostly stalkless except for the lowest leaves, often with a few widely spaced teeth but may be toothless, becoming smaller, narrower, toothless, alternate floral bracts on the upper stem. Branches form on the basal stem, producing dense, erect masses. Stems are sometimes purplish, can be smooth or have fine, short hairs, but leaves are typically smooth throughout.