Freshwater Ascomycetes - Species Monograph

Click on the pictures below to view them at their full size.

Genus	Species	Author
Ascitendum	austriacus	(Réblová, Winka et Jaklitsch) J. Campb. et Shearer
Class	Order	Family
Sordariomycetes	Sordariales	Annulatascaceae

Genbank ID: 293433

Synonymy:

Basionym: Ascolacicola austriaca Réblová, Winka et Jaklitsch. Mycologia, 93: 487. 2001

Description

Habit:

Saprobic on submerged wood.

Ascomata:

Ascomata on wood separate to clustered, densely aggregated in patches, immersed to superficial, black, coriaceous, globose to subglobose, ostiolate with a prominent neck, venter 350–585 x 295–505 µm.

Peridium:

Peridium in longitudinal section 28–42 µm thick, comprised of three layers: outer layer of pseudoparenchyma cells occluded with brown amorphous material; middle layer of brown, thin-walled, laterally compressed, elongated cells; inner layer of hyaline, laterally compressed, elongated, hyaline cells; in surface view, black, opaque.

Beak:

Beak central, cylindrical, periphysate, 85–300 (–460) x 50–140 µm, black at base, pale yellow at apex, wall 2-layered, outer layer of dark brown, laterally compressed thin-walled cells occluded with brown amorphous material, inner layer of laterally compressed thin-walled hyaline cells.

Hamathecium:

Hamathecium paraphysate; paraphyses longer than asci, 120–190 µm long, 4–10 µm broad at base, tapering to 2–3 µm, 1–9 septate.

Ascus:

Asci functionally unitunicate, cylindrical, 100–160 x 4–6 µm, expanding up to 260 x 8 µm in water, separating from the hymenial layer, pedicellate, with a prominent cylindrical to flaring apical apparatus, 2.5–3.5 µm long, 3.0–3.8 µm wide at apex, 2–3 µm wide at base; ascus apparatus MLZ negative, staining positive in aqueous cotton blue (for mature asci only) and nigrosin, discharging ascospores through the ascus apical ring or by dissolution of lower 1/3 to 1/2 of ascus when in water.

Ascospore:

Ascospores pale brown, fusoid, curved, 3 septate in sequence 2:1:2 or 3:1:2, 14–27 x 4–9 µm, middle cells darker than outer cells, each cell with a single large guttule, not constricted at septa; septa prominent, pigmented brown, with small refractive dots at ends; wall roughened in a striated pattern.

Sheath:

Not present.

Appendage:

Not present.

Culture:

Colonies on PYG agar immersed, brown, spreading, comprised of brown, septate, branched hyphae.

Anamorph:

None observed

Other info

Type & Location:

AUSTRIA: Wien 19, Hermannskogel, on submerged wood of Fagus sylvatica, 29 Aug 1998, W. Jaklitsch, WJ 1131-98 (HOLOTYPE, PRM 842991).

Other Specimens:

Canada (Ontario and Manitoba), the USA (AR, IL, ME, MN, MS, NC, NH, NY, OR, TN, VA, WI) and Venezuela. Detailed collection information is available from the authors and has been deposited with the herbarium specimens (ILL).

Substratum:

Submerged corticated or decorticated wood; causes soft-rot cavities in balsa wood in culture.

Habitat:

Lentic and lotic habitats.

Distribution:

Widespread.

Pertinent Literature:

Réblová and Winka 2001; Campbell and Shearer 2004.

Comments:

Additional Pictures

Ascus
Ascus apical rings
Ascus apical ring and ascospore striations
Ascospores
Ascospore striations
Ascospores & apical ring
Back door ascospore discharge.
Back door ascospore discharge.

Back