Pucciniastrum epilobii

The primary hosts of Pucciniastrum epilobii are species in the family Onagraceae, including Willowherbs and Fuchsia.  Minute powdery yellow-orange uredinia are borne on the leaves and occasionally stems, usually on leaf undersides.    The telia are subepidermal.

The alternate aecial host is a Silver-fir.  It is not a gall-causer on either host.

Puccinia pulverulenta affects willowherbs, pruducing orange aecia, chestnut brown uredinia and brown telia, all on leaf undersides, 

host

Photograph the rust on the host.   Ensure you have noted the host-plant species in your comments.  On willowherbs, a close-up photograph of the uredinia is needed, or confirmation by an expert before submission to Naturespot.

Willowherbs and Fuchsia