Freshwater Ascomycetes - Species Monograph

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Genus	Species	Author
Ophioceras	commune	Shearer, J.L. Crane & Chen
Class	Order	Family
Sordariomycetes	Inc. sed.	Magnaporthaceae

Genbank ID: 85942

Synonymy:

Description

Habit:

Saprobic on submerged woody and herbaceous debris.

Ascomata:

Ascomata 150-350 x 260-400 µm, immersed to superficial, scattered to clustered, black, globose to elongated globose, often oriented horizontally on the substratum, with a long beak.

Peridium:

Ascomal wall about 42 µm thick, fairly even in thickness throughout, two-layered; inner layer of hyaline, small pseudoparenchyma cells, outer layer of pseudoparenchyma cells occluded with brown amorphous material.

Beak:

Beak centric to eccentric, 375-1660 x (10-)30-100 µm, periphysate, wall two-layered, inner layer of parallel, laterally compressed pseudoparenchyma cells with darkened walls, outer layer of large, globose pseudoparenchyma cells with darkened walls.

Hamathecium:

Hamathecium of hyaline paraphyses longer than asci; paraphyses broad at base, tapering to a point, 2-3 septate, 210-348 x 9.7-13.0 µm.

Ascus:

Asci basal and peripheral, cylindrical, sigmoidal, arcuate to sigmoid, 64-118 x 4-12 µm, with eight ascospores in a single fascicle, with thimble-shaped ascus apparatus, 1.5-2 x 1-1.5 µm, staining blue in aqueous cotton blue, separating from hymenial layer.

Ascospore:

Ascospores filiform, arcuate, sigmoidal, hyaline, 3-7 septate, 50-110 (x = 80, s = 13, n = 135) x 2 µm, uniform width throughout or one end more broadly rounded than the other, (Figs. 16, 19), end cells staining blue in aqueous cotton blue; ascospores frequently released by deliquescence of basal half of ascus.

Sheath:

Appendage:

Culture:

Colonies on CMA, pale cream-colored, immersed with some aerial hyphae, compact with even margin.

Anamorph:

None observed.

Other info

Type & Location:

HOLOTYPE. PANAMA. Barro Colorado Island: A dried culture on alfalfa stems, isolated from a twig submerged in Allee Creek, Barro Colorado Island, Panama, 15 Apr 1983, CK. Augspurger, CS-408-2, ILLS, ATCC 56672.

Other Specimens:

USA. ILLINOIS: Union County, Pine Hills Swamp, on submerged wood, 17 Jan 1974, CAS & JLC, CS-408-1, ILLS; on decorticated wood, 24 Jun 1994, CAS, A-46-2, ILLS; on submerged wood, 3 Sep 1994, JLC & CAS, A-72-9, ILLS; Vermilion County, Jordan Creek, on submerged maple wood, 7 Nov 1980, CAS, J-132-1, ILLS, on submerged cottonwood, 7 Nov 1980, CAS, J-132-2, ILLS; on submerged sycamore wood, 7 Nov 1980, CAS, J-132-3, ILLS; on submerged, decorticated woody debris, Johnson County, Cache River, 10 Mar 1992, CAS & JLC, A-72-1, ILLS; LOUISIANA: LaSalle Parish, Little Pond, Catahoula National Wildlife Refuge, on submerged, decorticated wood, 8 Nov 1992, JLC & CAS, A-72-2, ILLS; INDIANA, McCormickÕs Creek, on submerged herbaceous debris, 27 Aug 1988, CAS, CS-835-1, ILLS; Shades State Park, small stream, on submerged herbaceous debris, 27 Aug 1988, CAS, CS-835-2, ILLS: MINNESOTA: Univ. of Minnesota Forestry and Biology Station, North arm of Lake Itasca, on submerged reed, 30 Jul 1992, CAS & JLC, A-72-5, ILLS.

Substratum:

Submerged woody and herbaceous debris.

Habitat:

Lotic, Lentic (streams, rivers and lakes).

Distribution:

Panama (Barra Colorado Island); U.S.A. (IL, LA, MN)

Pertinent Literature:

Shearer, C.A., J.L. Crane, and W. Chen. 1999. Freshwater Ascomycetes: Ophioceras species. Mycologia 91: 145-156.

Comments:

Additional Pictures

Ascospore
Ascus with deliquescent base
Asci
Partially empty ascus
Ascus with partially deliquescent base

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