Ann. Bot. Fennici 44: 35–78 ISSN 0003-3847 Helsinki 28 March 2007 © Finnish Zoological and Botanical Publishing Board 2007 Bryophyte flora of the Huon Peninsula, Papua New Guinea. LXX. Sematophyllaceae (Musci) 1. Acanthorrhynchium, Acroporium, Clastobryophilum, Pseudopiloecium, Radulina and Trichosteleum Benito C. Tan1, Timo Koponen2 & Daniel H. Norris3 1) Department of Biological Sciences, National University of Singapore, Singapore 119260 2) Finnish-Chinese Botanical Foundation, Mailantie 109, FI-08800 Lohja, Finland; and Botanical Museum (Bryology), P.O. Box 7, FI-00014 University of Helsinki, Finland 3) University Herbarium, 1001 VLSB, University of California, Berkeley, CA 94720, USA Received 14 June 2004, revised version received 21 Mar. 2006, accepted 30 Mar. 2006 Tan, B. C., Koponen, T. & Norris, D. H. 2007: Bryophyte flora of the Huon Peninsula, Papua New Guinea. LXX. Sematophyllaceae (Musci) 1. Acanthorrhynchium, Acroporium, Clastobryophilum, Pseudopiloecium, Radulina and Trichosteleum. — Ann. Bot. Fennici 44 (Supplement A): 35–78. The family Sematophyllaceae (Musci) of western Melanesia, mainly Papua New Guinea, is revised based on recent collections preserved at the Botanical Museum of the University of Helsinki. For western Melanesia, 18 genera and ca. 80 species of Sematophyllaceae have been reported in the literature. Of these, six genera, Acanthor- rhynchium M. Fleisch. (one species), Acroporium Mitt. (16 species), Clastobryophi- lum M. Fleisch. (one species), Pseudopiloecium Bartr. (one species), Radulina W.R. Buck & B.C. Tan (four species), and Trichosteleum Mitt. (seven species), are treated in this paper. Trichosteleum streimannii B.C. Tan, T.J. Kop. & D.H. Norris is decribed as new for science. Three new combinations are made and 12 new synonyms proposed (indexed). Trichosteleum sematophylloides Dix. is lectotypified. Six taxa are reported as new to Papua New Guinea: Acroporium adspersum (Hampe) Broth., A. microcladon (Dozy & Molk.) B.C. Tan var. burleyii B.C. Tan, A. rigens (Dix.) Dix., A. stramineum (Reinw. & Hornsch.) M. Fleisch. var. hamulatum (M. Fleisch.) B.C. Tan, Pseudopi- loecium acroporoides (Dix.) B.C. Tan, T.J. Kop. & D.H. Norris, and Radulina hamata (Dozy & Molk.) W.R. Buck & B.C. Tan var. scaberula (Mont.) B.C. Tan, T.J. Kop. & D.H. Norris. In addition, 14 taxa are reported as new to the Solomon Islands (indexed). A key to all species dealt with is provided, and illustrations provided for the new species and species not previously illustrated. The taxonomy, habitat ecology, and distribution in western Melanesia, as well as total ranges, are given for every species. A selection of previously published illustrations and an index of epithets of taxa dealt with are given. Key words: Acanthorrhynchium, Acroporium, Clastobryophilum, distribution, Musci, nomenclature, Pseudopiloecium, Radulina, Sematophyllaceae, taxonomy, Trichoste- leum 36 Tan et al. • ANN. BOT. FENNICI Vol. 44 Contents Introduction .............................................................................................................................................................................. 37 Family Sematophyllaceae Broth. 1908 ...................................................................................................................................... 37 Genus Acanthorrhynchium M. Fleisch. ..................................................................................................................................... 38 Acanthorrhynchium papillatum (Harv.) M. Fleisch. .................................................................................................................. 38 Genus Acroporium Mitt. ............................................................................................................................................................ 39 Acroporium adspersum (Hampe) Broth. .................................................................................................................................... 41 Acroporium angustum (Broth.) Broth. ....................................................................................................................................... 41 Acroporium convolutum (Bosch & Sande Lac.) M. Fleisch. var. horridulum (Bartr.) B.C. Tan, T.J. Kop. & D.H. Norris, comb. nova ................................................................................................................................................................... 43 Acroporium diminutum (Brid.) M. Fleisch. ............................................................................................................................... 44 Acroporium hermaphroditum (Müll. Hal.) M. Fleisch. ............................................................................................................. 45 Acroporium lamprophyllum Mitt. var. lamprophyllum .............................................................................................................. 47 Acroporium lamprophyllum Mitt. var. percaudatum (Bartr.) B.C. Tan, H.P. Ramsay & W.B. Schofield .................................. 47 Acroporium microcladon (Dozy & Molk.) B.C. Tan var. microcladon ..................................................................................... 48 Acroporium microcladon (Dozy & Molk.) B.C. Tan var. burleyii B.C. Tan ............................................................................. 48 Acroporium plicatum Bartr. ....................................................................................................................................................... 49 Acroporium rigens (Broth. ex Dix.) Dix. ................................................................................................................................... 49 Acroporium rufum (Reinw. & Hornsch.) M. Fleisch. ................................................................................................................ 50 Acroporium secundum (Reinw. & Hornsch.) M. Fleisch. .......................................................................................................... 50 Acroporium seriatum Bartr. ....................................................................................................................................................... 51 Acroporium sigmatodontium (Müll. Hal.) M. Fleisch. .............................................................................................................. 51 Acroporium stramineum (Reinw. & Hornsch.) M. Fleisch. ....................................................................................................... 52 Acroporium stramineum (Reinw. & Hornsch.) M. Fleisch. var. stramineum ............................................................................ 52 Acroporium stramineum (Reinw. & Hornsch.) M. Fleisch. var. hamulatum (M. Fleisch.) B.C. Tan ........................................ 53 Acroporium stramineum (Reinw. & Hornsch.) M. Fleisch. var. turgidum (Mitt.) B.C. Tan ...................................................... 54 Acroporium strepsiphyllum (Mont.) B.C. Tan ........................................................................................................................... 54 Acroporium strepsiphyllum (Mont.) B.C. Tan var. strepsiphyllum ............................................................................................ 55 Acroporium strepsiphyllum (Mont.) B.C. Tan var. divaricatum (Bartr.) B.C. Tan .................................................................... 56 Acroporium warburgii (Broth.) M. Fleisch. ............................................................................................................................... 56 Genus Clastobryophilum M. Fleisch. ........................................................................................................................................ 57 Clastobryophilum bogoricum (Bosch & Sande Lac.) M. Fleisch. ............................................................................................. 57 Genus Pseudopiloecium Bartr. ................................................................................................................................................... 58 Pseudopiloecium acroporioides (Dix.) B.C. Tan, T.J. Kop. & D.H. Norris, comb. nova .......................................................... 58 Genus Radulina W.R. Buck & B.C. Tan .................................................................................................................................... 59 Radulina hamata (Dozy & Molk.) W.R. Buck & B.C. Tan ....................................................................................................... 59 Radulina hamata (Dozy & Molk.) W.R. Buck & B.C. Tan var. hamata ................................................................................... 59 Radulina hamata (Dozy & Molk.) W.R. Buck & B.C. Tan var. elegantissima (M. Fleisch.) B.C. Tan, T.J. Kop. & D.H. Norris ............................................................................................................................................................. 61 Radulina hamata (Dozy & Molk.) W.R. Buck & B.C. Tan var. scaberula (Mont.) B.C. Tan, T.J. Kop. & D.H. Norris .......... 61 Radulina laevi-hamata (Dix.) B.C. Tan, T.J. Kop. & D.H. Norris ............................................................................................ 62 Radulina pendens (D.H. Norris & T.J. Kop.) B.C. Tan, T.J. Kop. & D.H. Norris ..................................................................... 64 Radulina weidenii (Zanten) B.C. Tan, T.J.