Is it possible to get another photo with something in it for scale?  If not, can you give me an idea of how big the overall plant is, where it's growing, are the leaves waxy feeling, etc?

I'd venture a guess at this point that it is in the mustard family but there are a few other possibilities.  Any additional information you can provide would be helpful.

Thanks,.

Thanks for getting back to me. I have taken three more pics. The plant is growing in my garden. I would say that the leaves feel a bit leathery rather than waxy. There is little vertical growth but lots of horizontal. Lots of pink tinges.

Thank you for the additional photos.  While I still can't give you a very definitive answer I may be able to narrow down the likely candidates.  Given the size, I don't think it's a member of the mustard family but rather a member of the evening primrose family, most likely one of the Oenothera species.  There are several native to Wyoming but there is one in particular, Oenothera biennis, common evening primrose, that is not but has been found in neighboring states.
 
Common evening primrose can be a biennial or winter annual which would explain what you are seeing in your garden at this time.  It is most often considered a weed and somewhat difficult to control.  If you only have a single plant in your garden, you might want to let it grow some more, possibly even flower, and then take it into your local Extension Office for a positive identification.

The Extension Office in Cody information is here:  
http://www.uwyo.edu/ces/county/park_cody/personnel.html
 
and the office in Powell information is here:
http://www.uwyo.edu/ces/county/park_powell/personnel.html
 
Both locations have a part-time horticulturalist that may be able to further identify the plant once it develops more characteristics.
 
This is the best identification I can give at this point, not having the actual plant in my possession, and I hope you find the information useful.
 

Thank you. I will let it sit there for awhile anyway.