Robin's Pincushion

In fact there are a cluster of them here growing on a stem of a wild rose. The pincushion is a type of harmless gall made by a tiny gall wasp during the late summer.  The wasp injects a certain chemical which causes the plant to make this irregular structure and inside the many grubs of the wasp feed off the matter until they emerge in the spring as fully formed adults.  As the months go by the pincushion takes on more of a pinky/red hue.