Venomerald

The venomerald replaced its ancestor the branching cellulosebane. Due to the arms race with branchcrytstal crystalplaque and the diveskimos it evolved a new tactic. Rather than producing "cellulase" it now produces the deadly venom "tetrodotoxin". Tetrodotoxin blocks the nerves by binding into the pores of cell membranes. This means that species like diveskimos will become paralyzed if they try to eat their spores. This venom is present in its airborne spores as well as seeps the chemical into the soil.

Now not producing "cellulase" the branchcrytstal crystalplaque no longer infect them since they have no "cellulase" to eat. And the arboreal diveskimos no longer feed on their spores. In addition to deter fauna from bothering it its roots now have sharp spikes. These spikes also contain tetrodotoxin, thus any fauna that run into them will become paralyzed.

In short rather than causing mass extinctions around it like its ancestors it makes it extremely difficult to feed upon or even go near.