Highlights of the Didymellaceae - Studies in Mycology

AveSkAMp et al.
Fig. 6. Phoma brasiliensis (CBS 120105a). A–C. Fourteen-day-old colonies on OA (A), MEA (B) and CHA (C). D–E. Pycnidia. F. Section of the pycnidial wall. G. Conidia. Scale
bars: D = 200 μm; E = 100 μm; F–G = 10 μm.
Etymology: Epithet refers to the country of origin, Brazil.
Conidiomata pycnidial, mainly solitary but also confluent, globose
to irregularly shaped, glabrous, on the agar surface and immersed,
(220–)250–370(–550) × (150–)190–290(–320) μm. Usually
with a single inconspicuous non-papillate ostiole. Pycnidial wall
pseudoparenchymatous, composed of 5–9 layers of oblong to
isodiametric cells, 18–27 μm thick. Conidiogenous cells phialidic,
hyaline, simple, smooth, globose to flask-shaped, ca. 4–5 × 3.5–4
μm. Conidia variable in size, cylindrical, thin-walled, smooth,
hyaline, aseptate 6–9(–10) × 2–3(–3.5) μm, with (3–)4–6(–8) small
polar guttules. Conidial matrix white.
Culture characteristics: Colonies on OA 50–53 mm diam after 7
d, margin regular. Aerial mycelium sparse, tufted near the centre
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of the colony, white. Immersed mycelium hyaline. Abundant
pycnidia produced semi-immersed in concentric rings. Pycnidia
in the outer rings pale luteous, darkening towards the centre of
the colony via buff, honey, hazel to brown-vinaceous; reverse
concolourous. Colonies on MEA 59–63 mm diam after 7 d, margin
regular. Immersed mycelium completely covered by a mycelial
mat, which is densely floccose, greenish olivaceous to greenish
grey, with elements of citrine, olivaceous black and white; reverse
concolourous. Hyphae locally containing red amorphous chrystaline
material. Colonies on CHA 62–67 mm diam after 7 d, margin
regular. Aerial mycelium floccose, white. Abundant dark pycnidia
are formed on the agar surface. Application of NaOH results in a
luteous discolouration of the agar, later changing to reddish, best to
be observed on OA medium.