The genus Cladosporium and similar dematiaceous ... - CBS - KNAW

Schubert et al.
Fig. 48. Cladosporium variabile (CPC 12753). A. Survey of hyphae that grow on the agar surface. Some of the fungal cells have a swollen appearance and could develop into
a “foot cell” that gives rise to a conidiophore. B. A number of aerial hyphae obstruct the swollen, large structures on the agar surface, which give rise to conidiophores. Some
of them appear ornamented. C. A series of conidia formed on a conidiophore (bottom of the micrograph). D. Detail of the ornamented conidia. The ornamentations are isolated
and dispersed. Note also the ornamentation-free scar zone and the hilum of the left cell. E. Two conidia behind an aerial hypha. F. Two conidiophores forming secondary
ramoconidia. Note the bulbous shape of the spore-forming apparatus. This micrograph is from an uncoated sample. Scale bars: A–C, F = 10 µm, D = 2 µm, E = 5 µm.
Teleomorph: Davidiella variabile Crous, K. Schub. & U. Braun, sp.
nov. MycoBank MB504583.
Davidiellae tassianae similis, sed ascosporis maioribus, (22–)26–30(–35) × (7–)7.5–
8(–9) µm, et ascis latioribus, plus quam 18 µm.
Ascomata pseudothecial, black, superficial, situated on a small
stroma, globose, up to 250 µm diam, with 1–3 ostiolate necks;
ostioles periphysate, with apical periphysoids present; wall
consisting of 3–6 layers of dark brown textura angularis, textura
epidermoidea in surface view. Asci fasciculate, bitunicate,
subsessile, obovoid to broadly ellipsoid, straight to slightly curved,
8-spored, 70–95 × 18–28 µm; with pseudoparenchymatal cells
of the hamathecium persistent. Ascospores tri- to multiseriate,
overlapping, hyaline, with irregular lumina, thick-walled, straight
to slightly curved, fusoid-ellipsoidal with obtuse ends, widest near
the middle of the apical cell, medianly 1-septate, not to slightly
constricted at the septum, at times developing a second septum
in each cell, several ascospores with persistent, irregular mucoid
sheath, (22–)26–30(–35) × (7–)7.5–8(–9) µm.
Mycelium immersed and superficial, irregularly branched, aerial
mycelium twisted and spirally coiled, 1–3 µm wide, septate,
sometimes with swellings or small lateral outgrowths, hyaline
to subhyaline, smooth, walls unthickened, hyphae which give
rise to conidiophores somewhat wider, 3–4.5 µm, subhyaline to
pale brown, almost smooth to minutely verruculose, sometimes
enveloped by a polysaccharide-like cover. Conidiophores usually
macronematous, but also micronematous, arising terminally
from ascending hyphae or laterally from plagiotropous hyphae.
Macronematous conidiophores erect, more or less straight to
flexuous, often distinctly geniculate-sinuous forming lateral
shoulders or unilateral swellings, sometimes zigzag-like or
somewhat coralloid, nodulose, swellings at first terminal, then
becoming lateral due to sympodial proliferation, often as distinct
lateral shoulders, unbranched, sometimes once branched, 6–
180 × (2.5–)3–6 µm, swellings (3–)6–11 µm wide, septate, not
constricted at the septa, pale to medium olivaceous-brown or
brown, usually verruculose, walls somewhat thickened, about 1 µm
thick, sometimes appearing to be two-layered. Conidiogenous cells
integrated, terminal and intercalary, cylindrical, nodulose to nodose,
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