Gymnosporangium confusum Plowright, 1889
on woody Rosaceae
Crataegus monogyna (underside of the leaf); Amsterdam, Diemerpark
Mespilus germanica, Amstelveen, Thijssepark: upperside, with spermogonia
surface of the inner wall of the peridium
aeciospore
Crataegus monogya, Gramsbergen, Holthone © Arnold Grosscurt; identification tetative
gall sliced
gall
Aecia 1-2 mm high. The walls of the peridium cells have numerous, somewhat wavy length ridges, which distinguish this species from G. clavariiforme.
Aecia can also develop on young shoots, and then induce strong malformations. Gäumann describes this for G. confusum only, but it cannot be excluded that other Gymnosporangium‘s cause similar galls (Brian Spooner in litt.).
spermogonia, aecia
woody Rosaceae (Maloideae), oligophagous
Chaenomeles japonica; Cotoneaster integerrimus, melanocarpus, nebrodensis, niger, nummularius; Crataegus azarolus, elliptica, grandiflora, laciniata, laevigata, monogyna, orientalis subsp. szovitsii, pentagyna, pinnatifida, sanguinea, tanacetifolia; Cydonia oblonga; Mespilus germanica; Pyracantha coccinea; Pyrus communis; Sorbus aucuparia, latifolia, torminalis.
on Juniperus
gall
only telia, on swellings of the branches, ± conical, up to 8 mm high, yellowish brown when moist. Teliospores in two forms: hyaline, thin-walled, stout, and brown, thick-walled, slender; spores apically rounded. They are two-celled, each cell with 2 germination pores close to the separation wall; measurements 19-26 x 30-48 µm, pedicel up to 120 µm.
telia
Cupressaceae, monophagous
Juniperus oxycedrus, sabina.
Not on J. communis.
synonyms
Gymnosporangium oxycedri Bresadola, 1903; G. tauricum Eriksson, 1919.
notes
In connection with G. confusum en sabinae, Redfern & Shirley note that once in the UK on Juniperus chinensis another rust has been found, viz. Gymnosporangium asiaticum Miyabe 1904.
references
Bahcecioglu & Kabaktepe (2012a), Bahçecioğlu, Kabaktepe & Yildiz (2006a), Brandenburger (1985a: 29), Buhr (1964b), Dauphin & Aniotsbehere (1997a), Dervis, Dixon, Doğanlar & Rossman (2010a), Erdoğdu, Hüseyin & Suludere (2010a), Gäumann (1959a), González-Fragoso (1925a), Helfer (2005a), Henderson (2000a, 2004a), Klenke & Scholler (2015a), Llorens i Villagrasa (1984a), Poelt & Zwetko (1997a), Preece & Hick (1994a), Redfern & Shirley (2011a), Roskam (2009a), Termorshuizen & Swertz (2011a), Tomasi (2014a), Vanderweyen & Fraiture (2008a), Wilson & Henderson (1966a), Woods, Stringer, Evans & Chater (2015a).