In 1965, during fieldwork in the Mt. Wilhelm region in Papua-New Guinea (PNG), the first author discovered a strongly gelatinous Collema-like lichen ( Fig. 1) with a dark brown thallus and black apothecia, when collecting other lichens in grassland and on the bases of trees on the edge of a patch of a moss forest (Table 1). On closer inspection of the specimen, it proved to have simple spores and to be impossible to identify at that time, though it had a characteristic membranous, fenestrate thallus when dry, with a striking, strongly blue-green pigmentation in the epithecium of the apothecia and round, ornamented spores, 10–12 µm diam. The second author later identified it with the species Ramalodium fecundissimum described from the mountains of New Zealand by Henssen in 1999, a most interesting extension of its distribution area.
Ramalodium fecundissimum, detail of the PNG collection. Scale 1·5 mm. Photographed by Jan Berge.
Lichens found at the Ramalodium fecundissimum locality in New Guinea
* these numerical categories are intended to give some indication of the frequency of these species where encountered in the field but they are not quantitative.
The grassland vegetation where this terricolous lichen was found is described by Walker (Reference Walker1968) and the community would probably be best described by the “grass with forbs”. This grassland is apparently not a permanent feature of the area. The current woodland vegetation on Mt Wilhelm appeared in the last 10 000 years (Hope Reference Hope1976) after the disappearance of glaciers, and the grassland developed after the forest was burned by indigenous people within the last 1000 years. Aerial photographic evidence indicates that the grassland may well be re-colonized by forest within the next 300 years (Corbett Reference Corbett1987).
Although New Guinea has a very rich lichen flora, the Mt Wilhelm area has been explored only recently (see Aptroot et al. Reference Aptroot, Diederich, Serusiaux and Sipman1997; Aptroot Reference Aptroot2008, Reference Aptroot2009). Ramalodium is a small, little known and infrequently collected lichen genus. It has recently been placed in the Pannariaceae (Wedin et al. Reference Wedin, Wiklund, Jørgensen and Ekman2009) because of the simple spores, non-amyloid ascus tips and annular exciple (foreign to the Collemataceae), as well as on molecular evidence. At present the genus is known to contain six species, all in the Pacific region with the majority of species in the Australasian sector, the northernmost in Japan and the easternmost in southern South America. The type species, Ramalodium succulentum Nyl., is from Australia, and a nearer species Ramalodium neocaledonicum (Räsänen) Henssen occurs in New Caledonia.
Ramalodium fecundissimum appears to be an addition to the rather rare Austral element in the PNG flora, usually found at high levels (Jørgensen & Sipman Reference Jørgensen and Sipman2006), mainly on the generic level, for example Fuscoderma which also occurs in New Zealand. Ramalodium fecundissimum occurs on damp schistose soil at 700–1700 m in the Kaweka range (North Island) and Tasman Mts (South Island) (Galloway Reference Galloway2008). It has only been collected there three times, so that it is either rare or overlooked. Such a long distance extension of its range to PNG is surprising, though the habitat appears to be very similar, but naturally at a higher altitude being so close to the Equator. Other lichen species with similar disjunctions are not often encountered. Hypogymnia lugubris (Pers.) Krog which also occurs in South America, Australia and New Zealand, however, has a wider austral distribution (Elix Reference Elix1980). Bryoria indonesica (M. Jørg.) Brodo & D. Hawksw., also present in this locality (see Table1), is to our knowledge the only other lichen species at the moment known to occur disjunctively between New Guinea and New Zealand. However, it belongs to the Malayo-Pacific element (Jørgensen & Galloway Reference Jørgensen and Galloway1983) and accordingly may have reached New Zealand from the north. Ramalodium fecundissimum on the other hand, being an Austral species like H. lugubris, most probably spread northwards.
Specimen examined. Papua New Guinea: Bismarck Mountain Range, Mt. Wilhelm, SE end of lake Pinde, 3700 m, 1965, D. J. Hill 12569 (BG, BM).
DJH is grateful to the Royal Society of London for the receipt of a Leverhulme Studentship, which enabled his visit to New Guinea, and to the Australian National University for the use of their Research Station on Mount Wilhelm. Further thanks go to Jan Berge and Beate Helle for their assistance with the photograph and to Holger Thüs at the Natural History Museum, London, for help with the collections.
