There are a number of different kinds of evening primrose. The typical evening primrose has a few bright, yellow, four petaled flowers on the top which blossom by the evening and wilt by the next day. They will continue to put blossoms out over a considerable part of the season, proceeding in line above the old, on a flower stalk at the top; the lower ones forming distinct pods. The flowers have an "X-shaped stigma in the center of the flower, and reflexed sepals [pointing downwards]." Once you have first identified the evening primrose you will not have any difficulty thereafter. The stems of the evening primrose are often reddish in colour. The evening primrose likes dry sandy soil and can be readily found in the open, often where dry soil has been recently disturbed.
Edibility: A considerable claim by certain health research people has been made on behalf of this roadside plant with its little yellow flowers. The plant has been linked to a family of hormone-like substances known as prostaglandins. There are claims that prostaglandins once within the human system can help people with such diverse ailments as: "high blood pressure, ulcers, asthma, allergies, migraine headaches, arthritis, glaucoma, menstrual cramps and possibly some types of cancer." In the 1930s, a Dr. Goldblatt in England and Dr. Euler in Sweden independently identified prostaglandins. Euler named it on the basis that high concentrations were found in the prostrate gland. Prostaglandins, so we are told, is part of the larger picture which science is only just coming to grips with; that is, that certain essential substances are needed by cells if they are to function properly. Prostaglandins is one of these substances generally known as "essential fatty acids," EFA. Further, we are told, that EFA is not something that can be made up within the body, but rather must be taken in through a person's diet. The difficulty is that we run the risk of not taking in sufficient quantities of EFA "because of junk foods, an excess of the wrong fats, too much alcohol intake, and the aging process, itself ..." What we are told is that the oil of evening primrose is one of the very few substantial sources of prostaglandins.