DESCRIPTION: A frequent rust found on the leaves of the host, particulary young plants, where it causes numerous red raised blisters that bear orange aecial cups whose spores infect new plants. The aecial cups have a torn white margin and are usually numerous. SPORES: Aeciospores are sub-globose, almost smooth and are orange, 16-21 * 13-17µm. Uredospores are pale brown, globose to ovate, minutely echinulate and slightly larger with 2 equatorial pores, 17-22 * 15-18µm. HABITAT: On the leaves of Nipplewort. SEASON: Spring to summer. |
