Pigweed in pastures
Hi, I have horses on pasture. I have what appears to be several versions of pigweed in the pasture. One is the version in attached picture. Am I correct to call this "prostrate" pigweed? If so, is it particularly dangerous to horses? What types of pigweed are particularly dangerous and how do I ID them?
The plant in the photo is called oak-leaved goosefoot (Chenopodium glaucum). This is an introduced annual species in Michigan. It is in the Amaranth/Pigweed family.
Some information on the toxicity of plants in this genus can be found at the following link from Colorado State University
Based on that information it looks like large quantities would need to be consumed to cause concern.
There is a key available to ID plants in the Amaranth family on Michigan Flora at
https://www.michiganflora.net/family.aspx?id=Amaranthaceae unfortunately this can be quite cumbersome to work through. I would suggest trying the plant ID app called PictureThis (https://www.picturethisai.com/). The app will try to push you to pay for the premium version, but if you keep "X-ing" out of the pop-up windows then you can use the free version.