Asiatic Dayflower / 露草 [dew herb] Commelina communis is native to East Asia, and was cultivated in Japan as a pigment plant, for use in wood block prints and fabric dye. The earliest record of their existence in the United States is in a botanical collection where the plant specimen is dated 1898. They may also have been introduced as an ornamental, and have recently begun appearing in crops of Roundup Ready soy beans and corn. In this context, they seem to exhibit a resistance to glyphosate, the active ingredient in the herbicide Roundup, and thus have been labeled a “superweed.” In their native southeastern China, they have been recognized for their ability to thrive on copper mine tailings, where they tolerate heavy metals and accumulate them in their tissues, winning it the title of “hyperaccumulator.”

In current-day Japan, the plant is known by the common name 露草, with the character 露 translating to dew and 草 translating to herb or grass. This Japanese common name likely derives from the same quality that precipitated the English common name dayflower: each blossom produced by this plant lasts one day, opening early in the morning and withering by midday or early afternoon depending on heat and moisture conditions. Like many Latin names used in dominant Western science, the term Commelina was given to the group of plants commonly knowns as dayflowers by Swedish taxonomist Carl Linneus in the 18th century, apparently named for two Dutch botanists Jan Commelijn and his nephew Caspar who are said to be represented by the two petals of the dayflower, while communis simply translates to common.