Bryophyte Flora of Western Melanesia
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149 Tropical Bryology 2: 149-160, 1990 Bryophyte flora of Western Melanesia Timo Koponen Department of Botany, University of Helsinki, Unioninkatu 44, SF-00170, Helsinki, Finland Abstract. A project dealing with the hepatic and moss floras of New Guinea and the Solomon Islands has proceeded more than halfway. The revision of the flora is based on the study of ca 17000 specimens collected in 1981. Two new genera and ca 50 new species have been described in 33 published papers and seven manuscripts. Many families, genera and species not previously recorded for the area have been added to the flora. More than 300 names have been reduced to synonyms. The percentage of endemic species of liverworts (40 %) is higher than that of mosses (18 %). Most of the endemic species occur at elevations above 1700 m. The geological history of New Guinea suggests that these high altitude endemics may be relatively young, i.e. less than 10 million years old. The moss flora is more closely related to the floras of Indonesia and the Philippines and continental Asia than to that of Australia. This can be explained by plate tectonics. The altitudinal distribution of hepatic and moss floras partly coincides with the zonation of vegetation proposed earlier. Human influence on bryophyte floras is devastating but a part of the flora may survive in gardens and plantations. Introduction Our base in Papua New Guinea was the In 1981 D. H. Norris of Humboldt State herbarium of the Forest Division in Lae. University, Arcata and I made several The specimens were collected during many field trips in New Guinea in order to separate excursions, each lasting 1 to 2 collect bryophytes (Koponen & Norris weeks (Koponen & Norris 1983a, fig. 4). 1983a). The original idea was to publish a The field work was organized so that we list of our collections but the target covered different areas during each gradually changed to the preparation of a excursion. Most of the time we were complete flora of Western Melanesia (West collecting things unknown to us, so we Irian, Papua New Guinea and the Solomon tried to collect all different-looking plants Islands). Up to now 30 papers with a total in any one locality. When the type of of 780 pages have been published in the vegetation changed, or when we reached series entitled “Bryophyte flora of the another vegetation zone, we began Huon Peninsula, Papua New Guinea” collecting anew and once again tried to and 7 manuscripts (241 printed pages) cover all of the flora. By this means we have been accepted for publication hoped to discover the frequency of the (Appendix 1). taxa and their altitudinal ranges. Most of our collections came from high elevations, Material and methods higher than 1700 m altitude. The project 151 benefited greatly when Mr Heinar papers. Streimann (Canberra) sent us his large collections from Papua New Guinea. Results These specimens are mostly from lower elevations than our material and have Taxonomy and floristics of Musci proved an essential addition. Some other smaller recent collections have also been The papers published so far are listed in used. Appendix 1 and an index given to the genera treated. In each paper there are The first phase in writing the flora was the keys to the genera and species and specific preparation of checklists based on the descriptions. Ecological details based on literature. The checklist of hepatics (Grolle the labels of our collections are given, as & Piippo 1984) also gives many new well as distribution in Western Melanesia records for the area. The checklist of and world distribution. Family and generic mosses has not been published yet. These descriptions are not provided but, in most lists are used as the basis for distribution cases, there is a discussion or review of records in Western Melanesia and also as generic and family concepts based on the starting point for generic and family Brotherus’ (1924, 1925) work. revisions. We have tried to check the identity of all names recorded from West Schultze-Motel’s (1963) checklist of New Irian, Papua New Guinea or the Solomon Guinea mosses contains 826 specific Islands. In many cases the type specimens names. Our checklist including the have been studied. Voucher specimens of Solomon Islands, has 1026 names. One floristic records have been studied when new genus, Orthothuidium Norris & T. we did not find the taxon in question. The Kop., and 14 new species have been nomenclature has been checked from the described in the series (see the Appendix). original literature. Many records of species, genera and families new to the area have been added. The hepatic flora has been studied mainly However, many more names (ca 300 - this by Dr. Sinikka Piippo and the moss flora number includes synonyms in the by D. H. Norris and myself. We have Hepaticae), have been reduced to been fortunate in obtaining the synonymy. The numbers of species in the collaboration of many colleagues. The families studied so far are given in Table 1. plan has been to send our material and the However, there are some 23 families still checklist to specialists on the various not studied or currently under revision. families. Their role has been to identify the These include some large families such as specimens and to write the descriptions the Orthotrichaceae (68 species), and keys. Our part has been the general Hookeriaceae (89), Brachytheciaceae planning of the flora and the preparation (19), Sematophyllaceae (146) and of the lists of specimens, altitudinal Hypnaceae (96). Accordingly, we do not distribution maps and other pertinent yet know the total number of mosses in the information. flora of Western Melanesia. If the rate of new discoveries and synonymisation A separate series of floristic papers has continues at the same pace the final number been published under the name may be ca 830 moss species. The families “Bryophytes from Frieda River, East and and genera currently undergoing revision West Sepik Provinces, Papua New are the Amblystegiaceae (by R. Ochyra), Guinea” (Norris & Koponen 1985, Piippo Bartramiaceae, Meesiaceae and 1986, Norris et al. 1988). Thirteen new Spiridentaceae (by T. Koponen), Ectro- species have been described in these pothecium and related genera (by N. 155 Nishimura), Macrothamnium and the mosses new discoveries seem Schlotheimia (by D. H. Vitt), Sphagnaceae to be more numerous than (by P. Isoviita), Splachnaceae and reductions to synonymy. The Splachnobryaceae (by A. Koponen), checklist (Grolle & Piippo 1984) Neolindbergia (by H. Akiyama) and Hoo- includes 709 species but will keriaceae and Sematophyllaceae (by D. probably increase to ca 725 with H. Norris). the present rate of revision. Most of the hepatic families have been Our additions to the Western Melanesian treated (Table 2). The untreated flora are so numerous that it is not possible families are the Anthocerotaceae to list them here. It is clear that the flora is (10 species), Lepidoziaceae far from being completely known (see subfam. Bazzanioideae (ca 50 ), Hyvönen 1989). For example, we Aneuraceae (43), Marchantiaceae collected 38 specimens of the large (10) and what may prove to be the moss, Macrothamnium most time-consuming, the hylocomioides Fleisch. from the Lejeuneaceae (34 genera and 193 Huon Peninsula (Fig. 1). It was species). The first five are currently already known from 7 provinces in under review by Drs S. Piippo, N. New Guinea, but only one earlier Kitagawa, T. Furuki and H. record existed from the Huon Bischler. The first manuscript on Peninsula. Elmeriobryum philip- Lejeuneaceae by R. Grolle and S. pinense Broth. is another species Piippo has been sent to reviewers. often occurring in large quantities. Accordingly, work on the hepatic There are only two previous records flora seems to be proceeding more of it, under the name Calliergon quickly than that on mosses. A wilhelmense Bartr. We were even summarising paper giving a key to able to recognise it in the field. An Western Melanesian Hepaticae and equally common and characteristic, Anthocerotae is in press (Piippo but smaller, species proved to be 1990). A list of papers completed undescribed and has been named so far and an index to the genera Leptocladiella flagellaris T. Kop contained in them are given in & Norris (Koponen & Norris Appendix 1. 1985). Phytogeography Taxonomy and floristics of Hepaticae Hyvönen (1989) has carried out an bryo- geographical analysis based on 27 of the The treatment of liverwort taxa is 57 Melanesian moss families and on 298 similar to that of mosses. However, species and subspecific taxa. His most in most cases a detailed species remarkable finding is that the New Guinea description is given only for those flora is more closely related to the floras of species present on the Huon the Asian continent (43 % of the taxa in Peninsula. This procedure was common), Indonesia (68 %), Malaysia selected in order to avoid repeating (39 %) and the Philippines (52 %) than to the text of some recent monographs those of Australia (42 %) or New Zealand (e.g. Hattori 1982, Inoue 1984). (12 %). This agrees with the results One new genus Symphyogynopsis obtained from other groups of plants and Grolle, and 23 new species have animals (Whitmore 1987) and can be been described in the series. Unlike explained by plate tectonics. The latest 156 discoveries from the study of plate tectonics vegetation zonation and found some suggest that Tibet, Burma, Malaya, correlations. Bryophytes are more Sumatra, Borneo and Western Sulawesi conservative and wide-ranging than separated from Gondwanaland in the late vascular plants and their distribution Jurassic (160 Ma ago) and drifted away patterns can be used as an additional tool from what is now the Australian plate. It is in the identification of corresponding bioc- proposed that they have been permanently limatic areas.