Number sign. Not to be confused with the Chinese character äº, the sharp sign (â¯), the viewdata square (â), the numero sign (â), the equal and parallel to symbol (â) or the game Tic-tac-toe's grid. The symbol # is most commonly known as the number sign, hash, or pound sign.
The poison ivy rash is not contagious. When a person touches the poison ivy leaf, a substance on the surface of the leaf (a resin) rubs off. Over the next 48 to 72 hours the skin reacts to the resin by becoming red and developing bumps and blisters at and around the site where the resin was.
Poison ivy, poison oak, and poison sumac grow in wooded or marshy areas throughout North America. The plants arenât really poisonous. They have a sticky, long-lasting oil called urushiol that causes an itchy, blistering rash after it touches your skin. Even slight contact, like brushing up against the leaves, can leave the oil behind. Poison ivy and poison oak grow as vines or shrubs. Poison sumac is a shrub or tree.