Phytopathogenic Dothideomycetes - CBS - KNAW

Sizing up Septoria
Fig. 91. Stagonospora perfecta (CBS 135099). A. Conidiomata forming in culture. B. Ascomata forming in culture. C–F, I, J. Asci and pseudoparaphyses. G, H. Conidiogenous
cells. K. Conidia. Scale bars: B = 300 µm, all others = 10 µm.
fusoid-ellipsoidal with median septum, prominently constricted
at septum, tapering towards subobtuse apices, with 1–2 large
guttules per cell, thin-walled, widest just above septum in
upper cell, (20–)23–25(–27) × (5–)6–7(–8) µm. Conidiomata
up to 300 µm diam, brown, immersed, subepidermal, pycnidial,
subglobose with central ostiole, exuding crystalline to creamy
conidial mass; wall of 2–3 layers of brown textura angularis.
Conidiophores reduced to conidiogenous cells. Conidiogenous
cells phialidic, hyaline, smooth, aggregated, lining the inner
cavity, ampulliform to doliiform or subcylindrical, with several
percurrent proliferations near apex, 5–12 × 4–6 µm. Conidia
hyaline, smooth, thin-walled, subcylindrical to narrowly fusoidellipsoidal,
with obtuse apex and bluntly rounded base,
2–3-septate, slightly constricted at septa, with 1–2 large guttules
per cell, (19–)25–29(–32) × (6–)7(–8) µm.
Culture characteristics: Colonies on PDA flattened, convex, circular,
with white aerial mycelium, surface fuscous-black, reverse irongrey
to black, after 14 d, 8.5 cm diam; on MEA surface fuscousblack,
reverse olivaceous-black; on OA surface isabelline, reverse
fuscous-black.
Specimen examined: Netherlands, Limburg, Weert, Moerselpeel, on leaves
of Carex acutiformis (Cyperaceae), Sep. 2012, W. Quaedvlieg (holotype CBS
H-21320, culture ex-type CBS 135099 = S656).
Notes: Stagonospora perfecta is the first species with a confirmed
sexual state in the genus Stagonospora. Of interest is the fact that it is
didymella-like, rather than phaeosphaeria-like in morphology, which
also explains it clustering in the Didymellaceae. Morphologically S.
perfecta resembles S. vitensis (18–32 × 4–6 µm, 2–3(–4)-septate;
Ellis & Ellis 1997), but conidia are wider. Stagonospora perfecta is
closely related to S. pseudovitensis, though in the latter conidia are
slightly longer, more fusoid-ellipsoidal in shape, and lack a sexual
morph in culture.
Stagonospora pseudocaricis Quaedvlieg, Verkley,
Gardiennet & Crous, sp. nov. MycoBank MB804456. Figs
92, 93.
Etymology: Named after the species that it resembles,
Stagonospora caricis.
On sterile Carex leaves on WA. Conidiomata black, immersed,
subepidermal, pycnidial, globose, up to 400 µm diam, exuding a
short, hyaline cirrhus of conidia; wall of 3–4 layers of medium brown
textura angularis. Conidiophores reduced to conidiogenous cells.
Conidiogenous cells phialidic, hyaline, smooth, aggregated, lining
the inner cavity, ampulliform to doliiform, 5–9 × 5–8 µm; tapering
at apex with prominent periclinal thickening or 1–2 inconspicuous
percurrent proliferations visible at apex. Conidia hyaline, smooth,
thin-walled, granular, or each cell with a large central guttule,
subcylindrical to fusoid, apex subobtusely to obtusely rounded,
base truncate, (5–)6(–7)-septate, (35–)42–48(–50) × (6–)7–8 µm.
Culture characteristics: Colonies on PDA flat, circular, with appressed,
grey aerial mycelium, surface sepia, reverse olivaceous-black to buff,
after 14 d, 8.5 cm diam; on MEA umbonate, round, with appressed,
grey aerial mycelium with white patches, surface greyish sepia,
reverse fuscous-black to olivaceous-black; OA similar to PDA.
Specimens examined: France, Foncegrive, Rive de la Venelle, on Carex acutiformis
(Cyperaceae), Oct. 2012, A. Gardiennet (holotype CBS H-21318, culture ex-type
CBS 135132 = S610); ibed., S609 = CBS 135414).
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