Plant immune systems are not like those of animals. You can often just slap parts together and they will meld. This likely evolved from plants literally growi

Plant immune systems are not like those of animals. You can often just slap parts together and they will meld. This likely evolved from plants literally growing on top of each other, such as a small plant growing on top of a log. Neither plant would do well if an immune reaction was initiated every time two root systems met.