Gymnosporangium clavariiforme (Wulfen) de Candolle,1805

on woody Rosaceae

Gymnosporangium clavariiforme: gall on Crataegus monogyna

Crataegus monogyna, België, prov. Namen, Ave-et-Auffe © Jean-Yves Baugnée, det. Arthur Vanderweyen

Gymnosporangium clavariiforme: gall on Crataegus monogyna

underside, with aecia

Gymnosporangium clavariiforme on Crataegus monogyna

Crataegus monogyna: aecia with long peridia, at the underside of the leaf, Nieuwendam

Gymnosporangium cf clavariiforme: gall on Crataegus monogyna

Crataegus monogyna, Balloo © Ben van As (identification tentative)

Gymnosporangium cf clavariiforme: gall on Crataegus monogyna

same leaf, underside

gall

The aecia are sitting on a swollen part of the underside of the leaf, sometimes even on a fruit. Peridium cylindrical, 2-3 mm, fraying out at the tip. The cells of the peridium are densely and coarsely verrucose.

spermogonia, aecia

woody Rosaceae, oligophagous

Amelanchier ovalis; Aroniax prunifolia; Cotoneaster nummullarius; Crataegus azarolus, laevigata, macrocarpa, microphylla, monogyna, nigra, orientalis, pentagya, sanguinea, x sorbifolia; Cydonia oblonga; Malus domestica, sylvestris; Mespilus germanica; Pyrus communis, syriaca; Sorbus aria, arranensis, aucuparia, latifolia, meinichii, neglecta, torminalis.

Crataegus is the most important hostplant by far.


on Juniperus

Gymnosporangium clavariiforme

Juniperus communis: telia; Belgium, prov, Namur, Ave-et-Auffe © Jean-Yves Baugnée, det. A Vanderweyen

Gymnosporangium clavariiforme: teliospores

Juniperus communis, from González-Fragoso (1925a): teliospores

gall

The telia develop on the branches. They are shriveled and brittle when dry, not very conspicuous. Under rainy conditions, however, the swell very strongly and take an orange-red color. They are much higher than wide. The swelling is the result of the intake of water by the pedicels of the spores. The two-celled teliospores are long, 13-20 x 50-86 µm, other sources write 10-22 x 40-120 µm; each cell with 2 germination pores close to the separation wall. Sometimes witches’ brooms are formed.

telia

Cupressaceae, monophagous

Juniperus communis.

Klenke & Scholler mention J. communis only; Gäumann moreover lists J. communis subsp. nana, oxycedrus, rigida; other authors extend the list even further.

inquilines

Mycodiplosis gymnosporangii.

references

Bahcecioglu & Kabaktepe (2012a), Brandenburger (1985a: 29), Buhr (1964b), Bellmann (2012), Coulianos & Holmåsen (1991a), Dauphin & Aniotsbehere (1997a), Dervis, Dixon, Doğanlar & Rossman (2010a), Gäumann (1959a), González-Fragoso (1925a), Helfer (2005a), Henderson (2000a, 2004a), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Koops (2013a), Kozłowska, Mułenko & Heluta (2015a), Kummer (2012a), Llorens i Villagrasa (1984a), Maier, Begerow, Weiß & Oberwinkler (2003a), Poelt & Zwetko (1997a), Preece & Hick (1994a), Redfern & Shirley (2011a), Roskam (2009a), Ruszkiewicz-Michalska (2006a), Savchenko, Heluta, Wasser & Nevo (2014c), Termorshuizen & Swertz (2011a), Tomasi (2012a, 2014a), Tóth (1994a), Unamuno (1941b), Vanderweyen & Fraiture (2008a), Wilson & Henderson (1966a), Zhao, Liu, Li & Cai (2016a), Unamuno (1942a), Woods, Stringer, Evans & Chater (2015a).

mod 10.viii.2018