New Significant Moss Finds From the Chatham Islands
During February 2006 a team of botanists visiting the Chatham Islands lead by Department of Conservation, botanist Peter J. de Lange made a number of interesting vascular plant finds. Most of these have now been well documented. However, a few scraps of two mosses collected during the same expedition have got New Zealand bryologists very excited.The first, a tiny, rather non-assuming, dark-green, wispy moss, was gathered from small pools developed beneath the drip line of an overhanging steeply plunging basalt cliff overlooking the Pitt Strait. The other a bright yellow, tufted moss grew on the bark of Coprosma chathamica. Both were “chance” collections made simply because de Lange thought them unusual and wanted to know what they were.
Both specimens sat for some nine months unidentified in the Auckland Museum Herbarium (AK). It was only after attending a “Threatened Moss and Liverwort workshop” run by Landcare Research staff at the end of the November 2006 Cheeseman conference that de Lange remembered the specimens. In particular de Lange thought that the dark green wispy moss looked rather like reference specimens of Archidium elatum held by Dr Beever and available at the workshop for people to examine. Archidium elatum is an “Acutely Threatened/Nationally Endangered” moss otherwise known only from three gatherings made from the northern North Island and Bay of Plenty.
The specimens were initially forwarded by the staff at AK to Dr Jessica Beever who immediately recognised that the dark green wispy moss was indeed Archidium elatum. The yellow, tufted moss she identified as a species of the tropical moss genus Calymperes. Being somewhat unfamiliar with that genus Dr Beever had the specimens forwarded to the senior author of the upcoming New Zealand moss flora, Dr Allan Fife, who soon identified them as Calymperes tenerum – a tropical species whose nearest known locations to New Zealand include the Cook Islands, New Caledonia and to the west, northern Australia. The Calymperes find has delighted Dr Fife not only because it is a new species for the New Zealand moss flora but also because the previous record for the genus in New Zealand is based on an old gathering of C. graeffeanum purported to be from Raoul Island but made by a collector not definitely known to have visited there. Because no further collections of it have ever been made from the Kermadecs or New Zealand proper its claim to being part of the New Zealand moss flora has always been considered “doubtful”. It has been retained simply because no bryologist has ever visited the Kermadec Islands, and as such, moss experts have had to rely on what others have collected for them, so it may yet be there and have been overlooked. Therefore the Chatham Island Calymperes find removes any ambiguity surrounding the presence of this genus in New Zealand. Though of course, in a situation rather like that described for the Kermadecs, that specimen was not part of a deliberate moss collection by an avowed moss expert, it was simply collected because it looked “different”.
Currently the moss flora of the Chatham Islands stands at about 100 taxa, with only the one endemic species, Macromitrium ramsayae (A. Fife pers. comm.). The discovery of Archidium and Calymperes highlights the need for further moss surveys of the Chatham archipelago. Biogeographically both mosses add to the emerging pattern that the islands are a meeting point for northern and southern flora elements. This is a pattern now well known for the vascular flora and it is also evident in the marine macroalgae (W.A. Nelson pers. comm.) but it has hitherto not been recognised for the moss flora.
NZPCN acknowledge the helpful comments provided for this article by Dr(s) Allan Fife and Jessica Beever.
Posted: 19/12/2006