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on Petasites

Petasites hybridus, Vreeland: uredinia

detail

Petasites hybridus, Diemen: urediniospores

leaf in mid-September, its underside coloured red by telia

telia

gall

the teliospores are arranged like basalt columns, on top covered by a layer of a waxy substance. Initially they are one-celled, but in the end meiosis takes place, resulting in a chain of four haploid cells. Each one germinates under formation of a sterigma (picture above), on top of which eventually a spore will be formed (Mims & Richardson).

The uredinia and telia of Coleosporium species morphologically are indistinguishable. For pictures see for instance C. melampyri and C. tussilaginis.

uredinia, telia

Asteraceae, monophagous

Petasites albus, frigidus, hybridus, japonicus, kablikianus, paradoxus, radiatus.

synonyms

Coleosporium tussilaginis f. sp. petasitis Boerema & Verhoeven, 1972

references

Blumer (1946a), Brandenburger (1985a: 24, 648), Gäumann (1959a), González-Fragoso (1925a), Helfer (2013), Jage, Kruse, Kummer ao (2013a), Jage, Scholler & Klenke (2010a), Klenke & Scholler (2015a), Kruse (2019a), Mims & Richardson (2005a), Poelt & Zwetko (1997a), Riegler-Hager (2014a), Schmid-Heckel (1985a), Tomasi (2003a), Tóth (1994a).