Does anyone know what this stuff is?

[j&lfarms]

Anyone have a clue? Just started coming up in my pasture this year. They are in random groups slim and anywhere from 4-24 inches tall. I need to get rid of this!!!!

 

[tom4018]

Might check this out:

http://www2.ca.uky.edu/agc/pubs/AGR/AGR207/AGR207.pdf

 

[redcowsrule33]

Looks like pennycress. One of the species is being promoted as a biofuel, but in your case it's just a weed.

 

[NWMoAngus]

It does appear to be pennycress. It is a winter annual broadleaf. A shot of 2,4-D should do the trick.