If you turn the photo one turn clockwise, you'll be able to see it easier.

It's a harmless slime mold....not a mold or fungus but a very common and benign substance. Knock it off the foliage so that it doesn't block photosynthesis but other than that, do nothing.

There are thousands of kinds of slime molds...this one is often referred to as Dog Vomit.

if you have wood in your garden ... as in.. your mulch ... in the process of its decomposition ... all kinds of molds and fungus attack it ...

and as far as i am concerned.. its a free show of ma nature... not a single one of them require any action on your part .... and unless you get rid of the wood.. there is nothing you can do about it anyway ...

that said.. getting an ID.. and learning is highly approved.. knowledge is power ...

ken

ps: it should not even affect that green plant... since the green plant.. isnt dead wood ... it may be encircling it ... but it should NOT be attacking it [that said.. it could make a liar out of me.. lol]

Thanks so much for the info. It certainly does look like "dog vomit!"

This particular variety is most commonly associated with dead wood and plant debris, but will move across any surface in the quest for food.

Diane discovered this slime mold in its more mature, fruiting stage when it develops and disperses spores (that brown dust) .

Just remember, it is not a fungus or mold, but a big blob of protoplasm, a Protist.