Most animals let out a cry when they are wounded. But plants, without a voice to scream, instead let out a smell.

When plants are damaged, they emit a fragrance called green leaf volatiles, or G.L.V.’s. Most people have gotten a whiff of it  it is the smell of freshly cut grass.

But in the case of at least one type of wild tobacco plant found in the Great Basin desert of southwest Utah, it is an actual distress call. When the plant is attacked, the call triggers the arrival of bugs that act as little firefighters, according to a new study in the journal Science.