This spring in my garden a fungus appeared on that thug, O. umbellatum. It kills the leaves back, which eventually shrivel into black threads. The fungus doesn't spread, or more accurately, has not spread to other geophytes in the garden, even when infected leaves lay on other leaves. Does anyone know what disease this might be? I have only online references, and none of the pages I could turn up described this fungus. Kathleen PNW coast, z 8, and first day above 60F in weeks was today.