Ascominuta lignicola gen. et sp. nov. is described and illustrated based on a specimen collected on submerged wood in Hong Kong. Ascominuta lignicola is characterised by relatively small ascomata, globose, 4-spored asci, and ascospores with an elaborate sheath. Ascominuta lignicola is compared with Massarina, Mycosphaerella and Wettsteinina. The placement of Ascominuta in the Ascomycetes incertae sedis is discussed.
Key WordsAscomycetes incertae sedis; freshwater ascomycetes; systematics.We have been investigating the fungi occurring on wood submerged in freshwater Lee et al., 1998;Wong et al., 1999)
Materials and MethodsSubmerged wood was collected from the Plover Cove Reservoir and returned to the laboratory in sterile plastic bags. Samples were incubated in moist plastic boxes at room temperatur e and examined periodically over 2-3too.All measurements of fungal structures were made in water. Single spore cultures were obtained as follows: a suspension of the ascospores in sterile distilled water was pipetted onto potato dextrose agar (PDA) plates. Single ascospores were allowed to germinate (ca. 2d) and transferred to PDA plates for further growth. Ascospores were prepared for SEM following the methods used by Ho et al. (1999).
TaxonomyAscominuta V. M. Ranghoo et K. D. Hyde, gen. nov.Ascomata partim immersa vel superficialia, globosa, atrobrunnea vel nigra, solitaria vel aggregata. Peridium perithecii, 3-5-stratosurn, ex cellulis hyalinis extrinsecus textura angularis fuscaris compositum. Pseudoparaphyses cellulosae, breviter catenulatae, ad septa constrictae. Asci 4-spori, globosi, bitunicati, sine apparatu apicali. Ascosporae biseriatae, late fusiformes, 1-septatae, ad septum constrictae, hyalinae, muris laevigatae, tunica gelatinosa praeditae. Figs. 1-10 Ascomata 60-65/~m alta, 70-75/~m diam, superficialia vel partita immersa, globosa, atrobrunnea vel nigra, solitaria vel aggregata. Peridium perithecii, 10-15/zm latum, 3-5-stratosum, ex cellulis hyalinis, extrinsecus textura angularis fuscis compositum. Paraphyses ad basim 5-15x2-3/~m latae, cellulosae, breviter catenulatae, ad septa constrictae. Asci 25-30• 30/~m, 4-spori, globosi, pedicellati, bitunicati, sine apparatu apicali. Ascosporae 22-25x 8-10/~m, biseriatae, late fusiformes, 1-septatae, constrictae, hyalinae, muris laevigatae, tunica gelatinosa praeditae.Etymology: From the Latin, lignurn=wood, and -cola----dweller, in reference to the habitat on wood.