Matching Pairs Weed Species #1Online version Weed Species #1 by Hannah Horak 1 Common Milkweed 2 Canada Thistle 3 Buckhorn Plantain 4 Broadleaf Plantain 5 Common Sunflower 6 Bull Thistle 7 Common Cocklebur 8 Common Purselane 9 Cheat 10 Common Mallow 11 Common Chickweed 12 Black Nightshade 13 Barnyard Grass 14 Common Lambsquarter 15 Common Ragweed