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