A slender Whorled Milkweed stem and leaf whorls rising through white and tan Yarrow flower clusters. Both Whorled Milkweed (Asclepias verticillata) and Yarrow (Achillea millefolium) are present; the broad flat clusters are Yarrow. Photographed at Prairieview Education Center in Crystal Lake, Illinois. Field photograph by Brian Woolman for Where’s Wildlife. Original file: Whorled-Milkweed-Flower-Plant-DSCN5062.jpg.