Clover in my Angraecum magdalenae!
 

I have clover growing in my Angraecum magdalenae and some other weird thing growing in my masdevallia. Will the hurt the plant?

Does their presence mean I'm doing something wrong?

It probably won't do much but could theoretically steal nutrients from your plant. I would rip it out

clover is a pain to get rid of... at the very least keep ripping it out to prevent it from flowering and setting seed which would just further spread the oxalis in your pots.

No, you're not doing anyting wrong. If your plants are outside, the wind and even birds can drop the weed seeds. Just pluck them out like you would weed your garden.
Joann

Yeah, just keep weeding them.

Yes they can be damaging - the really fine roots can infiltrate every last void in the medium, suffocating the otrchid roots.

I do some pulling every time I visit the greenhouse, but got smart about a year ago, and keep a bottle of premixed Round-Up herbicide and a cup full of cotton swabs out there.

Dip the swabs in the herbicide, "paint" the leaves of the oxalis (wihtout touching the orchid), and it will die in fairly short order.

yes, my greenhouse is infested with oxalis...i plan to do a major job on the floors with roundup as soon as the weather breaks, i cant keep it pulled up!! it grows faster than anything i know of....definately keep it out of the orchids, it will break down the media and make it uninhabitable for the orchid....do not let anything but the orchid in pots...