Freshwater Ascomycetes - Species Monograph

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Genus	Species	Author
Jahnula	apiospora	A. Carter, Raja & Shearer
Class	Order	Family
Dothideomycetes	Jahnulales	Aliquandostipitaceae

MycoBank ID: 536906

Synonymy:

Description

Habit:

Ascomata scattered, superficial to partially immersed in wood; attached to the wood with broad, brown superficial, stoloniferous hyphae.

Ascomata:

Ascomata membranous, globose to subglobose, 250-–304 × 300–362 µm, black, ostiolate.

Peridium:

Peridium 40-–45 µm wide, composed of textura angularis in surface view, in longitudinal section peridial wall 6–10 cell layers wide, 30–33 × 15–19 µm, composed of an outer layer of thick-walled cells, occluded by dark black, amorphous material along the upper 2/3 of the ascomata; inner layer of moderately thick-walled, large, brown, isodiametric to angular cells, 12–26 × 5–11 µm wide.

Beak:

Beak absent. Ostiole circular, depressed; ostiolar canal periphysate; periphyses short, hyaline.

Hamathecium:

Pseudoparaphyses hyaline, trabeculate, narrow, branched and anastomosing above the asci, embedded in a gelatinous matrix.

Ascus:

Asci 108–140 × 14–22 µm (mean = 122 ×18 µm, n = 20), basal, bitunicate, fissitunicate, cylindrical to clavate, pedicellate, with or without an apical chamber; endoascus ca. 18 µm wide, extending to 160–190 µm in length, with eight, overlapping uniseriate to biseriate ascospores.

Ascospore:

Ascospores 30–40 µm long, 8–12 µm at the widest point, (mean = 35 × 8 µm, n = 40), 7–9 µm wide at the septum, fusiform, slightly constricted at the septum, darkened; apiculate, unequally one-septate, septum submedian, apical cell large, 19–25 µm long, basal cell shorter than apical cell, 11–14 µm long, slightly curved; hyaline when young, brown at maturity, multiguttulate, smooth-walled, lacking a gelatinous sheath or appendages.

Sheath:

None observed.

Appendage:

None observed.

Culture:

Single-spore isolates grown on Corn meal agar (CMA, Difco) growing slowly, reaching ca. 1–2 mm diam in 30–40 days, dark black, effuse; hyphae broad, thick-walled and constricted at the septa; no anamorph observed.

Anamorph:

None observed

Other info

Type & Location:

CANADA. Prince Edward Island, 46˚12'38''N, 63˚19'40''W, on submerged decorticated wood in a small creek beside dirt road near Bonshaw and Trans Canada, 13 October 2007, Adrian Carter, AC-706 (ILL).

Other Specimens:

Substratum:

Submerged woody debris.

Habitat:

Lotic (small creek).

Distribution:

Canada (Prince Edward Island).

Pertinent Literature:

Raja et al. 2008.

Comments:

Additional Pictures

Dehisced and undehisced bitunicate ascus.
Surface of ascoma.
Dehisced and undehisced bitunicate ascus.
Germinating ascospore.
Germinating ascospore.
Thin section of ascomal peridium.
Vegetative hyphae growing across wood surface.

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