My first posting. Seems an appropriate spot to discuss this.
I've trying to get information from experienced plant lovers, especially succulent growers. Since about 5 years ago I've begun to see a couple of spp. of lichens growing and slowly spreading on a few of my plants. I have a Bursera fagaroides that I've grown from seed begun in 1985 and it become covered to the point where I can tell its harming the tree. But my biggest concern is an old plant I've had since about 1985 also, Euphorbia handiensis. Because of its rarity in its habitat in the Canary Islands, I don't want this plant harmed. It also produces much seed every year. Also a very large Pachypodium lealii saundersii I own is starting to have many branches with it growing on them.
I know lichens produce chemicals which break down rock over time, so seems to me it may be detrimental to my plants. Its very difficult to strip off these plants. I've included a few images.
