Everybody farts—and by everybody, we mean humans, cats, goats, ferrets, frogs, whales, and scores of other animals, with the notable exception of octopuses, birds, and a few other species that aren’t burdened by excess gas. But what about cacti, ferns, and other common plants? Was our garden salad once capable of letting one rip?

If you define fart as the Merriam-Webster dictionary does—to expel intestinal gas from the anus—then no, plants don’t fart, because they don’t have anuses. However, they do expel gas (including methane, a greenhouse gas found in human and animal farts), so they basically fart in their own plantlike way. According to Popular Science, microbes in trees produce gas in much the same way that microbes in the human body break down food and create gas. Methane then seeps out of a tree’s bark or stems.

Biogeochemist Patrick Megonigal, an associate director of the Smithsonian Environmental Research Center, says it isn’t known if these “farts” provide some sort of benefit to the trees. However, researchers have found “that some trees fart more than others,” Megonigal told  PopSci.

The fact that some leafy, above-ground plants release methane was only discovered in 2006. It was previously known that swamp plants release methane, which bubbles up to the surface in mud or water, but scientists didn’t realize the same rule applies to other plants and trees as well.

Some plants’ farts are more obvious than others. According to a 2016 study published in Plant Physiology, “shy plants” (officially known as Mimosa pudica plants) are less shy when it comes to their flatulence. In fact, they have been known to release a smelly stench when they’re poked or prodded. Researchers believe that gas rich in sulfur compounds is released from tiny hairlike sacs that run along the plant’s root. Six other Mimosa species are also capable of farting, and researchers say this could be a defense mechanism used to ward off other plants that encroach on their personal space. So unless you want to wade through a cloud of sulfur-infused farts, steer clear.

[h/t Popular Science]