Meadowsweet rust gall Meadowsweet rust gall Triphragmium ulmariae is a species of fungus in the Sphaerophragmiaceae family. It causes meadowsweet rust gall, which develops as a chemically induced swelling, arising from the lower surface of the meadowsweet leaves. This common gall is caused by the foliar 'rust' fungus "Triphragmium ulmariae" (DC.) Link, 1825 . The fungus attacks the petioles and / or midribs of the perennial meadowsweet ("Filipendula ulmaria") plant, a member of the family Rosaceae, causing swelling and distortion. Sori develop with bright orange spores. The rust's spores reach the meadowsweet via air movements and are spread from the galls that develop
Stem rust the end of the growing season black telia are produced. For this reason stem rust is also known as 'black rust'. The telia are firmly attached to the plant tissue. The site of infection is a visible symptom of the disease. Pycnia appear on barberry plants in the spring, usually in the upper leaf surfaces. They are often in small clusters and exude pycniospores in a sticky honeydew. Five to ten days later, cup-shaped structures filled with orange-yellow, powdery aeciospores break through the lower leaf surface. The aecial cups are yellow and sometimes elongate to extend up to 5 mm