Erysiphe arcuata U. Braun, Heluta & S. Takam.

Data Set Maintenance: Data set compiled and standard item. Data set author(s): Schubert K. @EXCL@ Kainz C. (06-09-20).

Nomenclature: Current taxonomic status: accepted or basionymous. Taxonomic rank: species. Erysiphaceae Tul. & C. Tul.; Erysiphales.

Type Information: Basionym: Erysiphe arcuata U. Braun, Heluta & S. Takam.

Taxonomic Literature: Taxonomic notes: + hyphae branched, septate, 2-7 µm wide, hyaline, thin-walled, smooth; appressoria sometimes nipple-shaped but usually slightly to strongly lobed, 5-14 µm diam., solitary or in opposite pairs; chasmothecial peridium dark brown, multilayered, slightly transparent, cells polygonal, rounded to irregularly shaped (walls sinuous), 5-20(25) µm diam.; anchor hyphae scarce, about 7-12. Braun U. et al., Mycological Progress 5: 139-153 (2006).

Biogeography: Northern hemispheric. Continent: Asia-Temperate and Europe. Country or state(s): United Kingdom, Austria, Germany, Hungary, Poland, Switzerland (incl. Liechtenstein), Former Yugoslavia [incl. Bosnia and Herzegovina, Croatia, Macedonia, Moldova, Serbia and Montenegro, Slovenia] (Montenegro), and Ukraine; Transcaucasus (Armenia, Azerbaijan & Georgia) (Armenia) and Japan.

Ecology: Biotroph; phytopathogenic; growing on leaves (ectophytic, forming distinct or effuse patches, sometimes covering the entire upper leaf surface, thin, greyish white, inconspicuous on the lower leaf surface, often conspicuous above, evanescent to subpersistent), epiphyllous (mainly) or amphigenous, causing the growth of galls (rarely causing light distortions). Host or Phorophyte Taxonomy: Carpinus betulus L.; Carpinus, Betulaceae.

Reproduction Strategy: With sexual (and possible asexual) stages. Ascocarps: Cleistothecioid (chasmothecia), orbicular (subglobose, i.e. somewhat flattened below), scattered or in loose groups, (.075)-.08-.115-(.135) mm in diam.. Margin: External filaments present ((1)1.5-3(3.5) times as long as the chasmothecial diam., width equal throughout or somewhat wider towards the tip, up to 10 µm); not interlaced, circinate (tightly) or helicoid (subhelicoid to helicoid, not or only barely enlarged to slightly enlarged, rarely slightly narrowed), 90-360 µm long, 4-7-(8) µm in diameter, hyaline or pigmented (brown at the very base (below the septum)), numerous, (6)-10-20-(25) per mm², growing between the lower and upper hald of the ascocarp (mainly) or on the upper half of the ascocarp (occasionally), usually flexuose, stiff and straight (sometimes straight or almost so but mostly curved, often throughout, arched, sometimes somewhat geniculate), or geniculate (bent), smooth or rough (usually distinctly), thin or moderatly thick (walls usually thicker in the lower part, becoming gradually thinner towards the apex), not ramified (rarely branched in the middle), not branched, septate (with a single basal septum).

Asci: 4-10 asci per ascocarp, globose (broadly ellipsoid-saccate, ovoid), not stipitate or indistinctly stipitate, (45)-50-60-(65) µm long, (30)-35-45-(50) µm wide; dehiscence unitunicate.

Ascospores: 1–2, c. 4, or c. 8 per ascus, spores 2-5-6 per ascus, ellipsoid or ovoid, 15-25-(28) µm long, 10-17-(19) µm wide; septa absent; wall hyaline (or subhyaline).

Conidiomata: Present; hyphomycetous.

Conidiophores: Pseudoidium-type; not branched (more or less centrally arising between two hyphal septa, from the top of the supporting hypha, erect, straight or almost so, rarely curved or slightly flexuous-geniculate, foot-cells cylindrical, occasionally somewhat wider below, basal septum occasionally 5-10 µm away from the supporting hypha, followed by 1-2(4) shorter cells); basal cells 20-50-(70) µm long, 5-11 µm wide. Conidium Formation: Conidiogenous cells single or in chains (occasionally in short chains of mature conidia ('pseudochains')). Conidia: Ellipsoid, ovoid, doliiform, or cylindrical; macroconidial (l/w ratio 1.5-3, germ tubes subterminal, short to moderately long, mostly with a terminal lobed appressorium, longer ones sometimes with a knob-shaped appressorium), not branched, 25-45 µm long, 10-19 µm wide; aseptate; without distinct fibrosin body fibrosin bodies.

(report generated 04.Okt.2007)