When you’re spending time outdoors this summer, in your own yard or hiking in a park, it’s useful to know to spot poison ivy.

The plant may have yellow or green flowers or yellow-green berries, depending on the time of year. Like poison ivy and poison sumac, poison oak releases an oil called urushiol when it sustains damage.

Poison ivy (Toxicodendron radicans) is a vine that contains an oily resin known as urushiol. According to the Centers for ...