Can I leave this piece off valve cover?

[Fengzheng1223]

Folks I have a 2013 x5 xdrive35i. I recently did a valvetronic change out and when I put the valve cover back on there was a piece fell off. The base actually fell off so I can't simply put it back on without gluing. Was wondering if someone can help me understand what's the function of this piece and if I can just leave it off?

Thanks,
Bob