A rust alternating between two hosts: the spermogonia and aecia affect Fleabane (Pulicaria dysenterica) and the uredinial/telial stages affect  rushes (Juncus spp.) . 

Orange-brown uredinia erupt from the stem, leaves and flower heads of the rush.  The telia are darker.

host

Photographs of the rust on the host.  You must record the host plant species.

Primary host is a rush (Juncus); aecial host Fleabane. Marshland, wetland, water body margins