Rare moss species remains elusive

An exclusive but elusive moss remains incognito after a team of scientists failed to find the mysterious didymodon calycinus in an expedition to Mauriceville last week.
The five-strong team was led by Auckland-based botanist Jessica Beever and included local Department of Conservation staff and bryologists from Wellington who searched for four hours in the area but returned empty-handed.
"It (moss) was first collected by William Gray, who farmed in the Mauriceville district for over 40 years. Gray sent specimens that he collected in 1913, and again in 1914, to H.N. Dixon, a moss specialist in England," she said.
"Dixon recognised it as a species new to science, and formally named it. He noted that it was "a very marked species", and that "the original locality, Mount Bruce, Wairarapa, is the only known station".
Later Dixon sent some of this material back to New Zealand, to G.O.K. Sainsbury, a Wairoa lawyer, who, in middle-age, had taken up an interest in mosses and had become New Zealand's leading expert on these plants, Dr Beever said.
Today the parts of the specimens returned to New Zealand by Dixon are housed, with the rest of Sainsbury's herbarium, in the Te Papa Tongarewa museum in Wellington.
The portions Dixon kept, including the holotype (the part from which the original description of a plant was made), are today housed in The Natural History Museum in London.
In 1956 Sainsbury found the moss on a damp roadside bank north of Waipukurau alongside the Mauriceville discovery almost 100 years ago these are the only known localities where this moss has ever been found.
"I have searched for it in vain at Sainsbury's site, which is now shaded by large macrocarpa and pines, and very dry, conditions which are probably unfavourable for the moss," Dr Beever said.
"Recently I have been able to borrow the Didymodon calycinus specimens from London, and study them in Auckland, in the herbarium at Landcare Research.
"There is a roughly-written pencil label on the holotype, most likely in Gray's hand-writing, giving more precise locality data. Dickson apparently did not send this information to Sainsbury when he returned part of the specimens.
Dr Beever said the search for the moss is something of a detective story and that DOC has ranked the moss as "nationally critical" with the same threat of extinction as the black robin and the white heron.
"We might have another look when it starts producing capsules and it's easier to see.
"We had five people who knew what they were looking for that's 20 man-hours, and we gave it our best shot it certainly warrants further investigation."
However, the trip did yield some heartening results with the discovery of another threatened aquatic moss found "flourishing" along several urban sections of Masterton's Makoura Stream, Dr Beever said.