Crops grown may include corn, alfalfa, timothy, wheat, oats, sorghum and clover. It is used to kill unwanted weeds such as dandelions, plantain, clover, and chickweed. They also like to feed on alfalfa and clover. Farms thus provided flowering clover and flower-rich meadows, favouring bumblebees. The trefoil knot is named after the three-leaf clover (or trefoil) plant. Isoflavones are commonly found in legumes such as soy and red clover. The footprint is similar to a 3 leaf clover and its stem. Some folk traditions assign a different attribute to each leaf of a clover. Fallon's monologue spot is noted by a painted four-leaf clover on the floor. She also appeared in the video for "Four Leaf Clover". To date, Sue is the only "4-leaf Clover" discovered. A duplicate experiment with a different sample of clover hay produced the same result. The activity in Clover Hill centered around Clover Hill Tavern. Warfarin is a derivative of dicoumarol, an anticoagulant originally discovered in spoiled sweet clover. Two species, clover glycine and trailing hop-bush, are nationally threatened.