Unknown/various species with similar appearances. May include Oenothera longissima, Oenothera elata, and most commonly O. villosa. All plants have yellow flowers with four, often veined petals. Each flower is short-lived, often blooming for only a few hours. Petals are delicate, and the flowers often crumple up (like wet tissue paper) and take on an orange hue towards the end of the day or in hot conditions. The plants tend to grow in disturbed soil. Different species vary in height.