Uromyces silphii Arthur, 1907

on Silphium

gall

Aecia yellow, cupulate, on discoloured spots at the underside of the leaves.

spermogonia, aecia

Asteraceae, monophagous

Silphium perfoliatum.

on Juncus

Juncus tenuis, Belgium, prov. Antwerp, Retie, Witte Netevallei, 29.viii.2020 © Carina Van Steenwinkel

uredinia

telia

urediniospore

urediniospore

teliospores

teliospore with pedicel

gall

Uredinia and telia amphigenous, light and dark brown, respectively. Urediniospores with two pores above the equator. Teliospores one-celled, smooth, wall apically strongly thickened; pedicel at least as long as the spore (up to 35 µm), often deciduous.

uredinia, telia

Juncaceae, narrowly monophagous

Juncus tenuis.

notes

This North American species was first discovered in Central Europe in 1956. The occurrence on Silphium seems not yet to be confirmed in Europe.

references

Beenken & Senn-Irlet (2016a), Brandenburger (1985a), Dietrich (2013a), Gäumann (1959a) Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Kruse (2014a, 2019a), Melzer, Pittoni, Poelt & Scheuer (1984a), Mułenko, Piątek, Wołczańska ao (2010a), Poelt & Zwetko (1997a), Termorshuizen & Swertz (2011a), Woods, Stringer, Evans & Chater (2015a).