Is that Wild Arugula? Identifying Edible and Medicinal Yellow-Flowering Plants

What is that yellow flower? Dandelion, Sow Thistle, Arugula, Goat's Beard or Wild Lettuce? All these are edible. Other yellow-flowered plants, like Celandine, St. John's Wort, Mullein and Agrimony, are medicinal. There are many more yellow-flowered plants in season at the moment, and I found a spot where a huge variety grow side-by-side. Come with me to identify and discuss as many as we can in the 2.5 hours available!