W.H. Ho

Fungal communities on submerged wood from streams in Brunei, Hong Kong, and Malaysia

Fungi on submerged wood in streams are a diverse group, comprising taxa from various families. Fungal communities on submerged wood collected from Sungai Sitam in Brunei, Tai Po Kau Forest Stream in Hong Kong, and from a stream in Lipur Lentang Nature Reserve in Malaysia are reported. One hundred and forty-seven taxa were recorded. A higher species diversity including temperate and tropical species was recorded in Tai Po Kau Forest Stream in the subtropics. Ascomycetes and their asexual stages were dominant in tropical and subtropical freshwater habitats, while discomycetes were rare in these habitats. Distinct fungal communities are found on submerged wood in tropical, subtropical and temperate regions and these are discussed. Including the fungi identified in this study, over 1000 fungi has been recorded from freshwater habitats.

New records and species of Sporoschisma and Sporoschismopsis from submerged wood in the tropics

During investigations of microfungi occurring on submerged plant material in tropical streams, seven species of Sporoschisma and one species of Sporoschismopsis were recorded. Three are newly described: Sporoschisma parcicuneatum, S. phaeocentri and Sporoschismopsis australiensis . Each of these species is described and illustrated in detail and a synopsis of remaining species of Sporoschismopsis is provided. Generic concepts and connections to teleomorphs are discussed and a key is provided to accepted species in both genera.

Ascomycetes from tropical freshwater habitats: the genus Savoryella , with two new species

Savoryella is reported from wood submerged in rivers and streams in Australia, Brunei, Hong Kong, Malaysia, Mauritius, the Philippines and South Africa. Six species are reported:- Savoryella aquatica, S. curvispora sp. nov., S. fusiformis sp. nov., S. grandispora, S. lignicola and S. verrucosa. A key to Savoryella species is provided and descriptions and illustrations of selected freshwater Savoryella species are given.

Four new species of Xylomyces from submerged wood

Xylomyces is re-examined, the type specimen X. Mamydosporis redescribed and illustrated, and new distribution records are provided. Four new species, X. elegans sp. nov., X. elegans sp. nov., giganteus sp. nov., X. punctatus sp. nov. and X. pusillus sp. nov. are described from wood submerged in freshwater collected in various countries. The chlamydospores of these species are drawn at the same scale as a composite diagram for comparison and each is illustrated with light micrographs. Xylomyces foliicola is regarded as atypical in the genus. A key to the accepted species in Xylomyces is provided.

Aquaphila albicans gen. et sp. nov., a hyphomycete from submerged wood in the tropics

Aquaphila albicans gen. and sp. nov. from submerged wood in the tropics is described and illustrated. It produces hyaline, multiseptate, fusoid or falcate conidia resembling the macroconidia of Fusarium species, but differs by its conidiogenesis and the aquatic habitat. The conidiophores of A. albicans are septate, hyaline, sympodially proliferating with conidiogenous denticles. Conidial development in A. albicans has been studied in culture and results are presented. The genus is compared with similar genera.

Acanthostigma and Tubeufia species, including T. claspisphaeria sp. nov., from submerged wood in Hong Kong

Acanthostigma scopulum, Tubeufia claspisphaeria sp. nov. and T. paludosa were identified from submerged wood collected in a small forest stream on Lantau Island, Hong Kong. The collections of Acanthostigma scopulum and Tubeufia paludosa differed slightly from the original descriptions. Tubeufia claspisphaeria differs from previously described species in that it has hook-shaped setae that form radially around the ostiole. This new species is described and illustrated and compared with the most similar species. A dichotomous key to the 16 accepted species in Tubeufia is provided.

Torrentispora fibrosa gen. sp. nov. (Annulatascaceae) from freshwater habitats

Torrentispora fibrosa gen. sp. nov. (Ascomycota, Annulatascaceae) is described based on specimens from submerged wood collected from streams in Tai Po Kau Forest Reserve, Hong Kong. T. fibrosa is characterized by immersed to superficial ascomata with a peridium of black cells arranged in irregular rows, wide septate paraphyses, long cylindrical asci with a relatively massive refractive apical ring, and unicellular ascospores with a fibrillar sheath. Illustrations from light and scanning electron microscopy are provided. It is compared with species in the genus Annulatascus, from which it differs in ascoma peridium and ascospore sheath morphology, and with other aquatic ascomycetes possessing ascospores with a similar fibrillar sheath structure.

Cataractispora receptaculorum, a new freshwater ascomycete from Hong Kong.

A new species of Cataractispora, C. receptaculorum, is described from freshwater habitats. This species is characterized by triseptate verruculose ascospores and polar appendages that unfurl in water. The ascospores lack polar chambers that enclose the appendages as in C. bipolaris and C. viscosa. An ultrastructural study of this species revealed that the ascus wall and apical ring of this species is typical of the Annulatascaceae, while the ascospore wall with verruculose ornamentations and the ontogeny of the ascospore polar appendages are similar to the other species of Cataractispora. Cataractispora receptaculorum is illustrated with interference light, scanning and transmission electron micrographs.

Can ascospore ultrastructure differentiate between the genera Linocarpon and Neolinocarpon and species therein

Ascospore appendages of two species of Linocarpon and three species of Neolinocarpon are illustrated using electron microscopy. The structure of these appendages can be used to distinguish between species. The ascospore appendages of species in both genera, however, were found to have similar structure. Thus, species of Linocarpon and Neolinocarpon could not be delineated at the generic level based on ascospore appendage structure.