Journal Number 93
November 2005


ORIGINAL PAPERS

Nematoceras "Pollok" - A new find for Awhitu
By Tricia Aspin

Isn't it perplexing how time, other commitments and sometimes pure supposition can turn spasmodic observations into lengthy and somewhat impatient waits - sometimes as long as another season or two? The latest exciting find for the Awhitu Peninsula stemmed from the frustration of taking something for granted. Now, one thing that has been learned is that one shouldn't take anything for granted - not in the orchid world anyway!

Ian and Pixie Craig's bush at Pollok is an interesting site offering several of the more unusual plants to be found on the peninsula. The Craigs farm large bullocks and the steep nature of the terrain allows for some disturbance by the cattle without causing much damage to the vegetation.

While botanising in March 2003 I found orchid leaves on two damp cliff faces in the native forest and noted that they looked like Nematoceras macrantha. Expectations of N. macrantha in flower during a later visit in October left me really brassed-off after finding all flowering finished and quite a lot of seed set. If this was definitely not N. macrantha then maybe it could be one of the Nematoceras rivularis aggregate here. None had been noted for Awhitu before.

Eager not to miss the crucial 2004 time of flowering the next visit to Pollok was at the beginning of July. There were many leaves with flower buds. Some emerging leaves were coiled like an ice cream cone. I had not seen this before. Most were little leaves that simply become bigger leaves. Flower buds were present (the "ice creams") in many of the coiled leaves.

19 July and Eric Scanlen and Allan Ducker joined the site visit. The south-facing sandstone cliffnever dries out in summer and has constant seepage. It was a wet winter and they wondered if there would be a waterfall to contend with - not so! The flowers were still not advanced enough to make a conclusion but it certainly seemed to be a N. rivularis form. Several smaller and less advanced colonies were found nearby.

Stella Christoffersen joined us on 10 August and we found the colony in full flower. (drawings pp22, 23). There were lots and lots of jaunty little fellows pertly staring straight at us from their perch. The largest colony of about 4 square metres had quite a dense covering of orchids. Approximately 50% of leaves had flowers. Eric and Allan had not seen one like this before. It is similar to Nematoceras "Kaimai" but there are differences. In between showers, the photographers captured images on film and videotape while the women checked out the seven smaller, nearby colonies. A rough estimate would be around 1500 plants in total.

Eric's photographs reveal little prickles all over the labellum apron and scores of little slanting ridges further inside (to give pollinators a firm foothold?) plus a green stripe leading down to the column. The labellum curling back on all the apron margins is unique. Compare the section with Bruce Irwin's excellent comparative drawings of the N. rivularis aggregate in J.86:16-19.

Specimens were sent to Dr Brian Molloy for DNA testing. To Brian it also appears to resemble N. "Kaimai" to some extent, but also N. "whiskers" [J63:8,9 & J86:19] and the tentatively named N. "aff. iridescens" [J89:7,8]. Because it is not a good match for any of these it will be subject to further critical examination.

Specimens were also lodged with Ewen Cameron at AK.

 

Map

Nematoceras Pollok

Flower

Flower Cross Section

Bruce Irwin received some specimens and has produced very fine detailed drawings of the same. He feels that his drawings show clearly enough that it is distinct from any known species and from any presently tagnamed. I am most encouraged by his comments.

Being thoroughly enthused, my husband Wayne and I have made further forays. Wayne's great interest is the kauri (Agathis australis) and we are always eager to spot showings of these. We are familiar with much of the Awhitu district and several searches produced likely sites but no orchids. I developed a hunch that we needed to look to the south of Pollok.

After some prompting, Stella remembered a waterfall area at Kohekohe which she had visited to photograph and paint about 12 years ago. On 9 September Stella pointed her nose in the right direction and led me to the grotto on Colin and Dorothy Hood's property. There is a large sandstone cliff forming a natural amphitheatre with a waterfall cascading over the highest part. It is a beautiful spot but no orchids were showing. The cliff continues up and around the north side of the watercourse, becomes moss covered where there is seepage and is open to good light before disappearing into a mass of kiekie (Freycinetia banksii). A scramble up over the slippery sandstone boulders and "Hey Stella, you're a whizz, we have it!"

This N. "Pollok" colony of about 18 square metres sported more than 1000 plants with an estimated 80% of leaves with a flower at this time. What a sight!  With so many, you really do feel as though they are staring at you. There were even many little glow worm threads visible in the fissures of the sandstone. Several flowers were past their best and already the ovaries were swelling.

Specimens were sent to Brian and Bruce for comparison and were confirmed as being the same.

In the meantime, Eric informed Peter de Lange of the find enclosing his photographs. While being involved in the excitement of the birth of a new baby son, Peter found time to recall having found something similar at Glen Murray in 1985, also on a south-facing wet sandstone cliff. Specimens sent to Brian had it reported as Corybas orbiculatus as was the convention of those days.

Coupled with Brian's and Bruce's comments the recording of this orchid, in two different places on the Awhitu Peninsula and the probable third at Glen Murray, must give weight to the fact that it is indeed a separate species. For the time being, I have pleasure in adding Nematoceras "Pollok" to the list of Awhitu orchids.

Now for a mention of some others.

More finds at Craig's include the first sighting of Ichthyostomum pygmaeum. The fact that it is growing on pohutukawa (Metrosideros excelsa) out on an otherwise bare ridge top and exposed to the westerly gales straight off the Tasman Sea is quite extraordinary. Others have since been spotted in the forested area but also on tall old pohutukawa's exposed to the winds. A fairly large branch felled by the gales and sporting a carpet of I. pygmaeum shows this orchid is indeed a tough one.

Winika cunninghamii also has a preference for pohutukawa as the host tree in this area. These plants too seem quite happy to cop the strong winds. Both of these epiphytic orchids have been elusive with only two W. cunninghamii previously discovered (one in Matakawau Reserve and one at Shepherd's in Boiler Gully Road).

During Eric's and Allan's 19 July 04 look at Craig's, we noted Diplodium alobulum in full flower, one colony forming a carpet at the base of a large pohutukawa and the other happily growing amongst native grass (Poa pusilla). There was also a small Nematoceras triloba agg. colony with several seed capsules and a solitary flower. First appearances suggested a N. "pygmy" taxon but after close observations Eric has these comments.

"It would seem that the little N. triloba agg. flower is N. 'tribrive', although why it was flowering a month early is a mystery. N. 'tribrive' does look a bit like N. `pygmy' ... But the node is well above the sheathing bract and its hang-dog dorsal sepal gives the show away. Cf. J89:29, bottom of the page. Comparing longitudinal sections of the two flowers is fairly convincing although my razor blade missed the exact centreline on Craig's so missed the pocket in the side of the labellum cleft. All N. triloba and N. macrantha seem to have pockets but this one is characteristic of N. 'tribrive' from the Bridal Veil Falls and from Pukapuka Track in the Hunua's. ... If it is N. 'tribrive' I'd be rather pleased because then it would have shown up in three well separated places which should consolidate it as an established taxon."

Further to the sometimes flummoxing Nematoceras triloba aggregate, last season saw two or maybe even three different taxa turning up. Specimens of the N. "pygmy 1" type flowering May/June in at least two relatively widespread sites (Matakawau Reserve at "Seat Junction" and "Outback" at Lee's) were sent to Brian Molloy for testing on 10 June 03. He commented that this taxon is quite different to N. triloba in the strict sense as well as other taxa within the complex and it seems to be the first to flower - June in this area through to August in the Nelson District.

There is Nematoceras "tridodd" flowering in August in at least three different sites (Dodd's Reserve, Lee's and Matakawau Reserve). These were first noted in 2001 [J81:22] and 2003 [J89:22-29]. Ian Dodd, a former NZNOG member, recognised the differences with this taxon in his reserve many years ago and sent specimens around but was told it was just a form of Corybas trilobus (which of course it is). Maybe with the renewed interest in the N. triloba agg. we will see his suspicions confirmed.

Eric says Nematoceras "trijuly " seems to show three forms. N. "trijuly 2" grows 20 metres west of N. "pygmy 1" at Matakawau Reserve, Seat Junction (drawing, J89 top left P27) and flowers later. Lee's Nematoceras "trijuly 3" was featured in J85:14 and again a year later from the same colony - drawings J89:27, left centre and left bottom and J89:29, photo at top right. Subtle similarities; subtle differences; all worthy of further detailed study.

Too often I am in Australia orienteering among their much more rampant displays of ground orchids when I know that back home our own little beauties are probably also in flower. It took two years to time it right for the flowering of a certain Petalochilus species here. There are a few plants in Lee's on a sunny clay track (Suite Ridge) and last 20 October, instead of unpacking the bags, I headed out for a look. Two were in flower. Not greenish-white like Petalochilus chlorostylus which occurs in the vicinity, but pink and the whole plants were slightly larger. With the help of the Field Guide and a phone call to Eric, the conclusion is that it is Petalochilus bartlettii - another for the list.

Nearby Thelymitra carnea was also in flower on this day, a bit later than the first recording on 10 Oct 01. This site sports only a few plants and the species hasn't been spotted elsewhere on the Awhitu Peninsula. No doubt they will be around. I just haven't found them yet!



Acknowledgements

Many people have contributed something to this article for which I am most grateful. They include; Ian and Pixie Craig, Colin and Dorothy Hood, landowners; my friend Stella Christoffersen and also Allan Ducker, sharing of knowledge on field trips; Bruce Irwin, drawings and comments N. "Pollok"; Peter de Lange, an interesting revelation from the past; Dr Brian Molloy, comments N. "Pollok"; Eric Scanlen, comments, observations, sharing of knowledge and photographs from field trips; Sid Smithies, photograph; my husband, Wayne, always supportive of my wanting to skive off orchid hunting.


Awhitu Orchids as at August 2004

Acianthus sinclairii, Chiloglottis cornuta, Corybas cheesemanii, Cyrtostylis oblonga, Danhatchia australis, Diplodium alobulum, Diplodium brumale, Diplodium trullifolium, Drymoanthus adversus, Earina aestivalis, Earina autumnalis, Earina mucronata, Gastrodia aff. sesamoides, Ichthyostomum pygmaeum, Microtis unifolia, Nematoceras macrantha, Nematoceras "Pollok"- the first found of the N. rivularis agg., Nematoceras triloba, includes the taxa under study (Nematoceras "pygmy" forms 1 and 2; Nematoceras "trijuly" forms 2 and 3; Nematoceras "tribrive"[?]; Nematoceras "tridodd"), Orthoceras novae-zeelandiae, Petalochilus bartlettii, Petalochilus chlorostylus, Pterostylis agathicola, Pterostylis banksii, Pterostylis cardiostigma, Singularybas oblongus, Thelymitra aemula, Thelymitra carnea, Thelymitra longifolia, Thelymitra aff. longifolia, Thelymitra aff. pauciflora, Thelymitra tholiformis, Winika cunninghamii.

 

 

 

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