Ultrastructure of ascus and ascospore appendages of the mangrove fungus Halosarpheia ratnagiriensis (Halosphaeriales, Ascomycota)

Halosarpheia Kohlm. et E. Kohlm is a genus of eighteen species, all of whic h have septate ascospores with unfurling polar appendages. Asci and ascospo res of Halosarpheia ratnagiriensis Patil et Borse were examined at the scan ning (including freeze-fracture) and transmission electron microscope level s. The ascus wall has two well-defined layers and the apical apparatus comp rises a refractive, electron-dense, lens-shaped disk embedded within a less electron-dense thickening. The ascospore wall comprises an episporium and a bipartite mesosporium, and the appendages are formed by extrusion of muci laginous material through an episporial pore field. Ascospore appendage ont ogeny is compared with other genera with unfurling polar appendages: Catara ctispora, Diluviocola, Tunicatispora, Tirispora, and Halosarpheia aquadulci s Hsieh, H.S. Chang et E.B.G. Jones and Halosarpheia heteroguttulata S.W. W ong, K.D. Hyde et E.B.G. Jones.