Kohlm. & Volkm.-Kohlm., Botanica Marina 48 (4): 312 (2005)








Pseudohalonectria Minoura & T. Muroi, Trans. Mycol. Soc. Jpn. 19: 132 (1978)

Type species:

Pseudohalonectria lignicola Minoura & T. Muroi, Trans. Mycol. Soc. Japan 19(2): 132 (1978)

Marine species:

Pseudohalonectria halophila Kohlm. & Volkm.-Kohlm., Botanica Marina 48 (4): 312 (2005)

Mycobank number: MB#357071                 Index Fungorum Number: 357071

Sexual morph: Ascomata 227-497 × 243-524 µm, solitary to aggregated, immersed to superficial, pale yellow at first, becoming darkened with age, rostrate; venter globose to flattened globose. Peridium membranous, tissue of textura angularis in face view, 13-15 cell layers thick, outer cells pseudoparenchymatic, darkened yellow and compressed laterally, inner cells pseudoparenchymatic, pale yellow. Neck 170-621 × 65-221 µm, long, cylindrical, periphysate, composed of parallel hyphae, outer hyphae ending in enlarged, outwardly directed, subglobose cells. Paraphyses longer than asci, wide at base, tapering to a rounded point, thin walled, attached to ascogenous hyphae, 108-198 × 3.6-8.4 µm at base, 1-5-septate. Asci unitunicate, cylindrical, straight or sigmoidal, with IKI-negative, thimble-shaped apical apparatus which stains bright blue in acidic aqueous cotton blue, containing 8 ascospores in two overlapping fascicles of four, 90-132 × 11-17.6 µm, separating at the basal septum from ascogenous hyphae and lying free in venter, lining the base and sides of ascomata. Ascospores yellow in mass, becoming orange brown with age, hyaline to pale orange brown in transmitted light, cylindrical with bluntly rounded apices, sometimes allantoid, 38.4-74.8 (x̅ = 62.6) × 3.6-6.6 (x̅ = 5.1) µm, 5-11-septate, not constricted at the septa, discharged forcibly or accumulating in a mass at the beak opening. Colony characteristics: Colonies on CMA floccose, appressed, white at first, becoming pale to lemon yellow, pale yellow in reverse, colony margin even. Hyphae septate, smooth walled, 1-2.5 µm diam., hyaline (Description from Shearer et al. 1989).

Saprobic on Juncus roemerianus. Perithecia 105-210 µm high, 95-185 µm wide, obpyriform, embedded in host, ostiolate with a long neck, periphysate, coriaceous, light to dark brown. Peridium 13-16 µm wide composed of two layers. Paraphyses thin-walled, septate, unbranched 5-6 µm wide. Asci 85-110 x 15-21 µm, 8-spored, rarely 4-spored, fusiform, short pedicellate, unitunicate, persistent, with a refractive tip, wedge-shaped ring. Ascospores 34-44 x 8-10 µm, biseriate, ellipsoid to fusiform, 5-7 (-8)-septate, full of oil globules, slioghtly constricted at the septa, hyaline to very light brown. Asexual morph: Undetermined.


Key references:  

Hu DM, Cai L, Hyde KD (2012) Three new Ascomycetes from freshwater in China. Mycologia 104: 1478–1489.

Minoura K, Muroi T (1978) Some freshwater Ascomycetes from Japan. Transactions of the Mycological Society of Japan 19: 129–134.

Shear CA (1989) Pseudohalonectria (Lasiosphaeriaceae), an antagonistic genus from wood in freshwater. Canadian Journal of Botany 67: 1944–1955.

Tubaki K, Ito T (1973) Reports of the Tottori Mycological Institute. (Japan) 10: 523–539.

Kohlmeyer, J.; Volkmann-Kohlmeyer, B.; Tsui, C.K.M. 2005. Fungi on Juncus roemerianus. 17. New ascomycetes and the hyphomycete genus Kolletes gen. nov. Botanica Marina. 48(4):306-317.


Key to the marine species of Pseudohalonectria:

1.Ascospores hyaline on wood, 6–16 septate, 97–166 x 4.2–5.8 µm                                                                          P. falcata

1.Ascospores hyaline to light brown, on Juncus roemerianus, 5–7 (–9) septate, 34–44 x 8–10 µm                               P. halophila

Type & Location:
Other Specimens:
On the salt marsh plant Juncus roemerianus.
North Carolina, USA
Pertinent Literature:
NOTE: The genus comprises circa 12 species mostly found on wood in freshwater habitats, two are marine usually on salt marsh plants (Jones et al. 2015). Pseudohalonectria Minoura & Muroi was introduced to accommodate P. lignicola, an ascomycete found on balsa wood submerged in a Japanese lake (Minoura and Muroi 1978). This genus is characterized of by colored perithecia with protruding, cylindrical, periphysate necks, unitunicate, cylindrical to clavate asci with an IKI negative apical apparatus; presence of paraphyses; and cylindrical, smooth, hyaline to slightly colored ascospores. Pseudohalonectria lignicola showed similar morphological features to Ophiobolus sp. (Tubaki and Ito 1973). However, Ophiobolus distinguishes from Pseudohalonectria as they produce bitunicate asci. Yellowish perithecia and long cylindrical ascospores of P. lignicola are very close to those of Halonectria milfordensis. Pseudohalonectria lignicola is different from H. milfordensis in its large septate ascospores, in its asci with a distinct apical ring, and in having paraphyses. Hu et al. (2012) confirmed the phylogenetic placement of Pseudohalonectria lignicola within Magnaporthaceae (Magnaporthales). Holotype HUT 40005, ex-type living culture HUT 4165. Poon and Hyde (1998) report on marine occurrence of the second marine species Pseudohalonectria falcata.


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