What is this weed?

Asked March 17, 2018, 12:31 AM EDT

I found this weed in some grass hay I bought south of Corvallis. The seed heads which are maybe a half an inch across have needle sharp spines. What is this weed and what can you tell me about it?

Benton County Oregon weed issues hay

2 Responses

Thank you for submitting the photos of the weed found in your hay. Unfortunately, I am unable to make a positive identification. It is possible that it is Navarretia squarrosa or Skunkweed, but again, I'm not certain, it's hard to tell from the photos. If possible, please bring a sample into the Extension Service office in Benton County.

I think I figured it out. It looks like buffalo bur, Solanum rostratum, according to Horse Owner’s Field Guide to Toxic Plants.