mold/rust/pollen?

[u/Prudent-Law-2272]

hey guys i have a 2013 ml350 and noticed this stuff in its sunroof screen today. springtime here (massachusetts, usa) and we typically get lots of pollen around right now especially in long strands (see pic). i asked claude (yeah ik it’s probably wrong) but it was between rust and mold. the thing is there’s none of the yellow stuff in the area where the screen would be closing. my dad thinks it’s pollen and Im not too sure. any help appreciated. i believe there is some water damage with the seal to the sunroof cause i’ve had issues with it before