Freshwater Ascomycetes - Species Monograph
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| Genus |
Species |
Author |
| Pseudotrichia |
allequashensis |
Fallah & Shearer |
| Class |
Order |
Family |
| Dothideomycetes |
Melannomatales |
Melannomataceae |
|
| Synonymy: |
|
Description
|
| Habit: |
Ascomata on grass stems immersed to erumpent, becoming superficial, covered with a tomentum of brown hyphae. |
|
| Ascomata: |
Ascomata 480–495 x 24–288 µm, immersed to erumpent, becoming superficial, pyriform, with bases immersed, dark brown to black, covered with a tomentum of brown hyphae. |
|
| Peridium: |
Peridium 31–39 µm wide, composed of 5–7 layers of cells; outer cells thickened and black, inner cells hyaline and of textura angularis. |
|
| Beak: |
Beak 184–190 x 100–112 µm, clypeate, periphysate, slightly thickened toward the apex. |
|
| Hamathecium: |
Hamathecium of trabeculate pseudoparaphyses less than 1 µm thick, in gel matrix, branching or at times anastomosing above the asci. |
|
| Ascus: |
Asci 136.5–156 x 11–16 µm, cylindric-clavate, with small ocular chamber, fissitunicate, thick-walled, tapering to a hoof-shaped stalk, fasciculate, basal, with 8 overlapping uniseriate ascospores. |
|
| Ascospore: |
Ascospores 24–31 x 4–6 µm, fusiform, with acute ends, hyaline, smooth, with 3 eusepta and 3 pseudo-septa, with a guttule in each hemispore, constricted at all septa, middle two cells larger than other cells, provided with a thick gelatinous sheath. |
|
| Sheath: |
Irregular gelatinous sheath surrounding ascospore; sheath not staining in India ink. |
|
| Appendage: |
Not observed. |
|
| Culture: |
|
| Anamorph: |
Not observed. |
|
Other info
|
| Type & Location: |
Allequash Lake, UTM Zone 16, 296454mE, 5101163mN, 46°2.032ÕN, 89°37.825ÕW, on submerged, partially decomposed grass stem, 17 June 1996, PMF & JLC P4-23 (ILLS 54061). |
| Other Specimens: |
|
| Substratum: |
Grass stem. |
| Habitat: |
Lentic. |
| Distribution: |
North America: USA (WI) |
| Pertinent Literature: |
Fallah & Shearer 2001. |
| Comments: |
This species fits well within Pseudotrichia. The genus currently contains four species, P. mutabilis (Pers. : Fr.) Wehmeyer, P. mamillata Barr, P. pachnostoma (Berk. & Curt. in Cook) Barr, and P. guatopoensis S.M. Huhndorf, all of which occur in the tropics (Huhndorf 1994). Among these species P. mutabilis is known also from North America (Barr 1990b). Huhndorf (1994) provided a key to species within Pseudotrichia. P. allequashensis differs from other species in the genus in having a narrow, cylindric beak with a clypeus, and hyaline ascospores that have 3 eu-septa and 2 pseudo-septa. The ascospore measurements of P. allequashensis are closest to the type of the genus, P. mutabilis, however, the latter species has brightly pigmented hyphal appendages on the ascomata and ascospores that are hyaline to light brown, with 1 to 3 septa. The tomentum found in P. allequashensis is of light to dark brown, rough-walled hyphae and very similar to that found in P. mamillata (Barr 1984), a species found on bamboo in Venezuela. Ascospore shape is similar in P. allequashensis and P. quatopoensis |
Additional Pictures
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Pict. 1, bar = 100 µm; pict. 2, bar = 25 µm; pict. 3, bar = 100 µm; pict. 4, bar = 25 µm; pict. 5 = 50 µm; remaining picts., bar = 25 µm.
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