#Marsh horsetail = #Equisetum_palustre #Field horsetail = #Equisetum_avense Today, a farmer told us something interesting just as he was about to head out to his cow pastures to control the horsetail. We chatted briefly, and he told us that he had no problem with field horsetail and didn’t do anything about it—it’s perfectly fine for the cows and is even considered a medicinal herb. However, he did have marsh horsetail, which is poisonous. Eating one or two here and there isn’t a problem, but in larger quantities, the cows would get sick. We weren’t familiar with marsh horsetail—they look very similar, he told us, but you can easily tell them apart with a simple test: grasp the leaf whorls together and hold them just above their lowest node—along with the stem. Now you pull off the leaf whorl and stem together. If the remaining stem is longer than the remaining leaf pieces, it’s the poisonous marsh horsetail; if the stem is shorter than the leaf pieces, it’s the non-poisonous field horsetail. Of course, we tested ours right away—it’s field horsetail. I only have one example photo of the poisonous one, but it’s just enough to illustrate the different heights of the nodes. Image 1: Marsh horsetail Image 2: Field horsetail Image 3: Marsh... Image 4: Field... Images 5–7: Pull test