The leaves of acacia trees protect from being eaten by producing a cyanogenic poison.

References

“The African acacias, well-protected though they may be by their thorns, use distasteful chemicals in their leaves as a second line of defence. Furthermore, and most remarkably, they warn one another that they are doing so. At the same time as they fill their leaves with poison, they release ethylene gas which drifts out of the pores of their leaves. Other acacias within fifty yards are able to detect this and as soon as they do so, they themselves begin to manufacture poison and distribute it to their leaves.” (Attenborough 1995:70)

Book
The Private Life of PlantsAugust 21, 1995
David Attenborough

Magazine article
Antelope activate the acacia's alarm system

Living System/s

Organism
WattleAcaciaGenus