Caryospora obclavata Raja & Shearer
Etymology: From Latin obclavatus in reference to the shape of the ascus.
Sexual morph: Ascomata on wood 290–320 × 290–340 µm, black, carbonaceous, scattered, partially immersed, erupting from the substrate, broadly conical, ostiolate, papillate. Papilla 50 × 80 µm, short, broadly cylindrical; periphyses not seen. Peridium 40–45 µm thick; textura angularis in surface view; in longitudinal section composed of two layers; inner layer of pseudoparenchymatic cells 5–10 × 3–5 µm, outer layer of black carbonaceous material. Pseudoparaphyses trabeculate, branched and anastomosing. Asci 115–160 × 32–50 µm (mean = 140 × 39 µm, n = 25), basal, bitunicate, fissitunicate, obclavate and broadly rounded at the apex, pedicellate, ectoascus splitting at the ascus apex, endoascus thick-walled, with a broad ocular chamber 13 × 12 µm, with eight ascospores, uniseriate at the apex and base and irregularly arranged in the middle. Ascospores 30–40 × 11–15 µm (mean = 34.5 × 13 µm, n = 30), broadly ellipsoidal to biconic, hyaline to pale green, becoming dark reddish brown at maturity, forming acicular crystals in glycerin or lactic acid, deeply constricted at the midseptum, slightly constricted below the apices; upper cell wider than basal cell, cells with one large guttule and several small ones; surface roughened; surrounded by a thin gelatinous sheath; sheath invisible in glycerin or lactic acid, 1-septate, but occasionally additional septa also seen near the tips of the ascospores. (Description from Raja and Shearer 2008)
Holotype: USA. FLORIDA: Apalachicola National Forest, Whitehead Lake, 30u099540N, 84u409300W, water 29 C, pH 7.5, on submerged decorticated woody debris, 13 Jul 2004, HAR and CB, F79-
Freshwater distribution: USA (Raja and Shearer 2008)
Raja HA, Shearer CA (2008) Freshwater ascomycetes: new and noteworthy species from aquatic habitats in Florida. Mycologia 100(3):467-489
Figure 59–70. Caryospora obclavata from the holotype, 59. Longitudinal section through ascoma, 60. Peridium, 61. Trabeculate pseudoparaphyses, 62. Young asci; note thick-walled apex, 63. Ascus with eight irregularly arranged ascospores, 64. Fissitunicate ascus, arrow indicates area where endoascus extends from ectoascus, 65. Endoascus showing apical chamber, 66. Endoascus with thickened apex showing ocular chamber, 67. Rough-walled ascospores, 68. Mature ascospore, 69. Ascospore showing thin gelatinous sheath, 70. Mature ascospores showing additional septa within endoascus. Scale bars: 59 = 50 µm, 60–70 = 20 µm.