It is an herbaceous annual plant in the dayflower family

It gets its name because the blooms last only one day

It is native throughout much of East Asia

In Japan, it is known as オオボウシバナ (Oboshibana) or アオバナ (Aobana ; literally means “blue flower”)

The flowers emerge from summer through fall and are distinctive with two relatively large blue petals and one very reduced white petal. It was used extensively as a colorant in 18th and 19th century woodblock prints in Japan