Can you identify fungus growth on trunk of pitch pine bonsai?
As answered on other photo:
We are not really sure what this is, and definitely cannot tell what type.
Fungus would have gills and spores,(perhaps beneath the structures you are seeing? Are we seeing stems on these?
Our specialists looked at your photos and wondered about liverworts, or perhaps even something growing from the plant food you are using. which contains fungi.
Many fungi grow on wet and dying wood. You should gently probe the root area of your bonsai and see if they are rotting or squishy.