Puccinia lagenophorae on Senecio vulgaris leaf
Puccinia lageniphorae is a common rust fungus that occurs on a large number of host plants. Among these are Senecio vulgaris (Groundsel) and Bellis perennis (Daisy). Both of these plants are common on campus. Groundsel occurs on disturbed ground, in flowerbeds and in paving cracks. Daisies, of course, are common in the regularly mown lawns.
Rusts have complicated life-cycles with different spore types being produced at different times of year. Puccinia lagenophorae is most easily spotted when it produces clusters of orange, cup-shaped aecia.
Puccinia lagenophorae on Senecio vulgaris stem
Although seeing a bulging length of stem, or a distorted leaf, with orange pustules breaking out can invoke a instant response of ‘Yuk!’ the orange aecia are actually really beautiful. The deep orange cup is surrounded by pale ‘teeth’. You can often see a dusting of the orange spores released on the nearby leaf surface.
This fungus originated in Australia where it transferred from other plants in the Asteraceae family to Groundsel plants which had been accidentally taken to Australia with imported plants and soil. The fungus probably made it to Europe in the same way – accidentally carried by humans moving infected plants. It has been in Britain since 1961. In 2000 it crossed the Atlantic to the USA where it infects Groundsel that arrived with European settlers in the 19th century.
