ENTERTAINMENT NEWS (CNN) — In case you missed out on National Grab Some Nuts Day back in August, lucky for you, October 22 is National Nut Day.

Most nut trees grow in warm environments, and a lot of nuts are native to the Southern Hemisphere. Here are five fun nut facts from the Australian tree nut industry group, "Nuts for Life":

- Ever wondered why you can't find cashews sold in the shell? That's because part of the shell contains urushiol, the same poison found in poison ivy.

- The first mention of hazelnuts can be dated back to a Chinese manuscript from 2838 BC.

- Brazil nuts are actually the seed of a very large tree found in the Amazon jungle, hence the name.

- Pistachios are the only (edible) nut that don't need to be shelled before you roast them.

- Bitter almonds contain hydrogen cyanide. Luckily, the type of almonds consumed commercially isn't the bitter variety.