Freshwater Ascomycetes - Species Monograph
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| Genus |
Species |
Author |
| Macrospora |
scirpicola |
(DC.) Karst |
| Class |
Order |
Family |
| Dothideomycetes |
Pleosporales |
Pyrenophoraceae |
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| Synonymy: |
|
Description
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| Habit: |
Ascomata scattered and immersed on dead, submerged macrophytes. |
|
| Ascomata: |
Ascomata scattered, immersed, becoming erumpent, globose, often flattened globose, papillate, 365–380 x 331–345 µm, appearing as small black dots on the surface of the substrate, densely tomentose, tomentum of light-brown hyphae. |
|
| Peridium: |
Peridium membranous, small-celled, of textura angularis in surface view and in longitudinal section; inner region 12–15 µm wide, composed of two to three cell layers of hyaline, laterally compressed fusoid cells, 10–16 x 2–6 µm; outer region of 5–6 cell layers, 25 µm wide, of dark brown, laterally compressed pseudoparenchymatic cells, 4–10 x 2–6 µm. |
|
| Beak: |
Absent; small, flattened lid present. |
|
| Hamathecium: |
Pseudoparaphyses cellular, numerous, slightly constricted at septa, narrow, 4–6 µm wide, extending from the base to the apex. |
|
| Ascus: |
Asci numerous, fissitunicate, 220–250 x 43 (-47) µm with eight biseriate ascospores, clavate to broadly clavate, tapering at the base to a short, claw-like stalk; ascus wall thickened at the apex, endotunicum with ocular chamber and thick walled, sometimes with two separable endotunica. |
|
| Ascospore: |
Ascospores initially hyaline becoming light brown, fusoid to oblong-ellipsoid, one cell wide in side view, two cells wide in face view, (47-)60-70 x 15.5–24 µm, with 3-5 transverse septa and a single longitudinal septum in each cell layer, constricted at septa, symmetric, ends broadly rounded or tapered or with one end broadly rounded and the other end tapered; longitudinal septa perpendicular or at a slight angle from the perpendicular to transverse septa; cells filled with lipid droplets. |
|
| Sheath: |
Sheath in water appears as a fusoid gelatinous structure, 8–12 µm wide at the mid-septum; in india ink, sheath is revealed to be bipartite with an outer amorphous part and an inner fusoid part. Both parts of the sheath elongate greatly in water (up to 1 mm). Spores germinate within the sheath shortly after settling on a glass slide. |
|
| Appendage: |
None observed. |
|
| Culture: |
|
| Anamorph: |
None observed. |
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Other info
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| Type & Location: |
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| Other Specimens: |
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| Substratum: |
Schoenplectus (Scirpus) lacustris |
| Habitat: |
lakes |
| Distribution: |
England |
| Pertinent Literature: |
Pringsheim, 1858; Ingold, 1955 |
| Comments: |
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Additional Pictures
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Thick walled endoascus
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Thick walled endoascus
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Tritunicate ascus
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Tritunicate ascus
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Newly released ascospores
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Sheath in indian ink
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Sheath in indian ink
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Sheath in indian ink
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Sheath in indian ink
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Sheath in indian ink
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Sheath in indian ink
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Sheath in indian ink
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