I only have experience with Ilex verticillata since I decidua doesn't grow anywhere I have lived and isn't common in commerce. Both are deciduous native hollies that prefer average to damp soil. Both have separate male and female plants like all hollies, so yours is female and there is a compatible male nearby since you have fruit. If this is a wild form, you can read about it (or also the various cultivated forms) by plugging in the name Ilex verticillata or Ilex decidua into the MO Botanical Garden's plant finder in the topmost blank on the form. You may find more locally pertinent info at the Ladybird Johnson Wildflower center's online database.

I found a plant out by the salt flats. It has orange berries on it. I've never seen it before. Does anyone know what type of plant this is. Thank you.

Hwy-great answer. Just went out and looked and yes-the leaves are perfoliate. Thanks a lot. A new one in my wild flower estate.

Sorbus, mountain ash.