On the leaves, petioles and stems of Valeriana sitchensis in Washington, Valerianella [Plectritus] congesta in Oregon (Suksdorf) and V. stenocarpa in Texas (Karliing), causing thickening and distortion of the infected organs ...

Synchytrium perforatuim stimulates the development of sporangial and resting spore galls ... which are ... composite and multicellular. ... The[ ] galls ... are commonly aggregated and frequently confluent ... They are formed by enlargement of the infected epidermal cell and division of the adjacent and bordering cells ...

[G]alls are embedded largely in the host tissue, and protrude only slightly above the surface. However, considerable proliferation of the host tissue occurs around the sites of infection so that raised humps of tissue are formed in which the galls occur ...

[T]he infected portions of the leaves may become 3 to 4 times their normal diameter ...