Monographs Details: Pseudonectria clusiae Samuels & Rogerson
Authority: Samuels, Gary J. & Rogerson, Clark T. 1990. New ascomycetes from the Guayana Highland. Mem. New York Bot. Gard. 64: 165-183.
Family:Nectriaceae
Description:Species Description - Perithecia solitaria, superficialis, nonstromatica, globosa vel subglobosa, 180-260 µm diam., nonpapillata; murus perithecialis rubrus, in acido lactico luteus, materia alba, amorphica, in K O H solubilis tecta. Asci angusti clavati, 50-70 X 7-10 µm, 8-spori, sessili, apicem annulo minuto refractili provisi. Ascosporae ellipsoideae, (8-)9-ll(-12.6) X (2.7-)3.2-4(-4.5)µm, 1-cellularae, hyalinae, laeve, 1-2-seriatae. Status anamorphicus ignotis.

Discussion:

Hab.: In foliis Clusiae sp.

Holotypus: Guyana (Samuels 4854, N Y ). Anamorph: None known

Perithecia solitary, superficial, non-stromatic, anchored to substrate by hyphae, easily removed from the substrate, globose to subglobose, 180- 260 Atm diam., nonpapillate, not collapsed when dry, wall red when dry and in 3 % K O H , yellow in 100% lactic acid, with a white furfuraceous coating on the perithecial wall, ostiolar area glabrous; the entire perithecium appearing white with a red, areolate apex; furfuraceous coating of amorphous material, dissolving in 3 % K O H. Cells at the surface ofthe perithecial wall angular in outUne, 10-20 µm, walls ca. 1 µm thick, not perforated by pores. Perithecial wall ca. 25 µm wide, exterior 1-2 layers of cells with angular to circular lumina, 5-10 µm, walls to 2 µm thick; cells of interior region ca. 10 µm wide, of 2-3 layers of cells with lumina elliptic to flattened, 10-15 µm long, walls ca. 2 µm thick but progressively thinner toward the locule. Perithecial apex of small, nearly circular cells with walls to 2 µm thick, ostiolar canal of narrow hyphal elements arising from the inner perithecial wall region and continuous with the periphyses. Paraphyses not observed among mature asci. Asci narrowly clavate, 50-70 x 7-10 µm, apex with a minute refractive ring, 8-spored, sessile. Ascospores ellipsoidal, (8-)9-ll(-12.6) x (2.7-)3.2- 4(-4.5) µm, unicellular, colorless, smooth, partially to completely biseriate in asci.

Habitat. Recently fallen leaves of Clusia spp.

Etymology of the Specific Epithet. Refers to the host plant.

Known Distribution. Guyana.

TYPE. GUYANA. Cuyuni-Mazaruni Region, VH: Mazaruni Subregion, VII-2, foothills immediately S of Mt. Ayanganna, ca. 1 km W of Pong River, 05º28'N, 60º04'W, elev. 550-650 m, on decaying leaf of Clusia sp., 26 Feb 1987, Samuels (4854), Pipoly, Gharbarran, Chin & Edwards (holotype N Y , isotype BRG).

Additional Specimen Examined. GUYANA. Mt. Wokomung, Wokomung Base Camp, ca. 8 hr walk NE of Kopinang ViUage in tall, wet forest dominated by Euphorbiaceae, 05°05'N, 59º50'W, elev. 1070 m, on decaying leaves of Clusia sp., Jun-Jul 1989, Samuels (6461), Boom & Bacchus (BRG, NY).

Notes. Pseudonectria clusiae is found only on leaves of Clusia species that have recently fallen. Because perithecia appear so quickly on these leaves, and not on leaves of other trees, it is Ukely that the species is an endophyte of Clusia.

The coating on the perithecial wall appears to be hyphal when observed at low magnification. In microscopic preparations in water no structure was observed. In K O H the coating came away from the perithecia in large sheets and then dissolved.

Ascospores of neither of the specimens cited above germinated on C M D at 20°C. Chaetopsina cf. fulva RambeUi accompanied P. clusiae on both of the collections (Fig. 41). The conidiophores were more robust, and the conidia much larger (17-18 X 2-3 Atm) than those described by Samuels (198 5) for the Chaetopsina cf. fulva anamorph of Nectria chaetopsinae Samuels.

Pseudonectria Seaver accommodates Nectria Fr. species that have superficial, non-stromatic perithecia and unicellular ascospores. It is a genus of fewer than ten described species, of which only a few have been critically examined. Pseudonectria clusiae is anatomically similar to P. rousseliana (Mont.) Seaver (Bezerra, 1963), the type species of the genus. Perithecia of P. rousseliana occur on living leaves of Buxus sempervirens L.; they are described as light orange to greenish and thick-walled setae arise from the surface of the perithecial wall.