Oxalis, which gave it's name to oxalic acid.
Oxalis /ˈɒksəlᵻs/ is a large genus of flowering plants in the wood-sorrel family Oxalidaceae comprising about 800 of the 900 known species in the family. The genus occurs throughout most of the world, except for the polar areas; species diversity is particularly rich in tropical Brazil, Mexico and South Africa.Eastern-Tailed Blue, a male from the powder blue on the upper surface of the wings.
Many of the species are known as wood sorrels (sometimes written "woodsorrels" or "wood-sorrels") as they have an acidic taste reminiscent of the unrelated sorrel proper (Rumex acetosa). Some species are called yellow sorrels or pink sorrels after the color of their flowers instead. Other species are colloquially known as false shamrocks, and some called sourgrasses. For the genus as a whole, the term oxalises is also used.
Blue Flag Iris, the native swamp iris. I took the starts for the blue flags in my pond from this very spot about 20 years ago.
Yellow Flag Iris, a non-native swamp iris, slightly larger and more robust than the Blue Flags, in the ditch/stream at the bottom of our back lots. Considered invasive, I don't see enough of them to be worried about them taking over.