A rather widespread psyliid gall on Juncus canadensis superficially resembling Rhynchospora macrostachya. Found it here: https://bugtracks.wordpress.com/2012/09/03/graminoids-galls/ along with a reference to an old (1916) article containing a black-and-white photo. Also, here it is at BugGuide: https://bugguide.net/node/view/1081765/bgimage