Hibiscus trionum, commonly called flower-of-an-hour,[2] bladder hibiscus, bladder ketmia,[2] bladder weed, modesty, puarangi, shoofly, and venice mallow,[2] is an annual plant native to the Old World tropics and subtropics. It has spread throughout southern Europe both as a weed and cultivated as a garden plant. It has been introduced to the United States as an ornamental where it has become naturalized as a weed of cropland and vacant land, particularly on disturbed ground.