Base of leathers toadstool

[JKDMan]

I have this toadstool leather and I noticed that right at the bottom of the stalk where the tissue meets the rock there is a tan colored portion of stalk all the way around is this normal?

 

[lapin]

Mine sometimes get a cyano or algae growth that looks like that

 

[JKDMan]

Mine sometimes get a cyano or algae growth that looks like that

Is that harmful.?

 

[lapin]

I dont think so. It has never effected mine