Misumena vatia is a species of crab spider with holarctic distribution. In North America, where it is the largest and best-known flower spider, it is called the goldenrod crab spider or flower (crab) spider, because it is commonly found hunting in goldenrod sprays in the autumn.
Young males in the early summer may be quite small and easily overlooked, but females can grow up to 10 mm (excluding legs); males reach 5 mm at most.
Crab spider is a common name applied loosely to many species of spiders, but most nearly consistently to members of the family Thomisidae. Among the Thomisidae it refers most often to the familiar species of "flower crab spiders", though not all members of the family are limited to ambush hunting in flowers.