Journal Number 89
December 2003

THE COLUMN

Nematoceras "pygmy" "trijuly" "tridodd" & "tribrive"
By Eric Scanlen

At Wattle Bay, Awhitu Peninsula, Ian Dodd showed Tricia Aspin and the Column a Nematoceras triloba agg. which had finished flowering on 20 Nov 2001 [J82:12] but whoops, it had its sheathing bract well below the petiole axis or node.

So the Column exclaimed that it was not N. "pygmy", which is common across the harbour entrance in the Waitakeres. Both his companions threw him sidelong glances at this blurted announcement but Tricia swiftly followed it up, two seasons later, flowering not in June or July but August; it wasn't N. "pygmy" was it? The much maligned sheathing bract was handy after all.

On 11 Aug 2003 the Column drove around the Manukau to record yet another exciting (?) N. triloba agg. addition to the list, in response to Tricia's call. How do you like Nematoceras "tridodd"? (triloba at Ian Dodd's place).

Colony 1 was on a closed-off farm track, in Podocarp-tawa forest, on ancient sand hills.
Colony 2, 50m away, was on the side of a low ridge in the same bush. Notice its notched dorsal
sepal and, what caught our attention mostly, the swept back bib to the labellum on mature flowers.

It raised tantalising memories of a Bridal Veil Falls denizen of Allan Ducker's on 30 Sept 1995; spotted again in a "quick" diversion from a nearby motor rally on 4 Aug 1997. Graham Marshall, the dedicated rallyist, seemed a bit agitated about the trials we were missing whilst the Column, efficiently as ever (?), photographed these odd, late flowering Corybas trilobus agg. Priorities do have to be maintained, don't they?

Slides were filed uneasily under C. "triju" - then later under Nematoceras "pygmy" so the taxon
went unreported these eight years. Now these pics came under close scrutiny and the Column
chose to follow his own advice, don't try to squeeze them into a taxon where they don't fit!
They were too big and flowered far too late to be N. "pygmy", nor were they N. "trijuly" nor
"tridodd". Yet another vexed N. triloba taxon?

More evidence was needed, so on 14 Aug 2003 at the Bridal Veil Falls (dropping into a basalt crater near Raglan) Phil Mitchell was duly impressed with a good showing of flower on, can we call it N. "tribrive"? (triloba, Bridal Veil Falls, Photo 2).

But Phil had spotted some N. triloba agg. during a tramp in the Hunua Ranges. So next day, some 3km from Lilburnes Road he indicated more of the same - N. "tribrive".

It is scattered along the Pukapuka Track, 94km from home, on a greywacke ridge, above the 440m mark where, no doubt, the added rainfall and higher humidity brought conditions closer to the spray zone around 55m Bridal Veil Falls.

This is the seventh and highest altitude N. triloba taxon recorded in the Hunuas where N. triloba is quite uncommon: which is good in a way, because there is so little chance of hybrids when colonies are kilometres apart. N. "tribrive" is recognisable from the dorsal sepal sloping down at 45° to the tip, almost parallel with the rearward-sloping ovary, the labellum cleft is closed for the bottom half and the sheathing bract is well below the node.

When the Column compared slides of N. "pygmy", "trijuly", "tridodd" and "tribrive" a figurative fog set in of similarities yet notable differences. New slides of N. "pygmy" from Geoff Stacey's Wharekawa garden (17 June 2003) and of N. "trijuly" (Photo 3) from Tricia Aspin's find at Awhitu Central (5 July 2003), far from clearing the air, only added to the fog. To begin with, minor nagging differences in N. "pygmy" itself needed sorting before any analysis of the new ones could begin. Below is what is still emerging.

From Journal articles, the Column's personal records and personal communications with finders, all N. "pygmy"s, flower from the end of May to the middle of July, from Bream Tail [J76:38] to Queenstown [Nwsltrs 22:2; 28:11]. They have the node at the mouth of the sheathing bract and the dorsal sepal overhangs the labellum a little.

Forms 1, 4 & 5 (detailed below), grow numerous, larger but sterile leaves in August.

Do forms 2 & 3 do the same? Beyond that there are obvious differences and the 5 or 6 forms below emerge from the Column's deliberations: What do you think?

		1. Dan Hatch's 1959 description of Corybas trilobus in Auckland's orchids [also Nwsltr 7:3] was in fact the Waitakere Ranges form of, can we now call it Nematoceras "pygmy" form 1?. It has leaf and flower spread apart, has a flat leaf from early bud and the labellum cleft is wide below like an angular open U. It grows in tight colonies from Matakawau to Wharekawa to Bream Tail to the Waitakeres. The Column's tag, Corybas "triju" [J76:39 fig. 6] was dropped because form 4 below was tagged earlier and C. "triju" also included Nematoceras "trijuly"!
		2. Allan Ducker spotted the N. "pygmy" form 2 in some mossy kanuka on stream flats between Mangawhai and Bream Tail Reserve. It has a contoured V form leaf, tilting away from the flower and an oval opening to the labellum. Plants are solitary, 500mm or more apart but more data is needed on this one.
		3. Geoff Stacey first picked up N. "pygmy" form 3 at Matingarahi just north of his Wharekawa Garden. It is the smallest of the lot. The notched labellum with a simple V cleft, sits right on the leaf, right into mid July and it grows in tight colonies. This form is also at Matakawau reserve.

4. Graeme Jane and Gael Donaghy spotted N. "pygmy" and first tagged it at Cape Farewell [J69:11; J73:11-13], budding from a vertically coiled leaf but with a flared labellum, unnotched bib in J73:12 but notched in J69:11 and cleft closed at the bottom.

It looks very much like Ian St George's from Five Mile Creek, Queenstown, (Photo below).  
Compare it with Gael Donaghy's shot in J69:11.

Nematoceras aff. trilobus
Five Mile Creek,
Queenstown
July 1984
(photo IStG)

5. Meanwhile, Brian Tyler and Geoff Monk (J84:36 and J88:25) have spotted colonies near Levin in Waitarere Pine Forest sand dunes (famed for Chiloglottis trapeziformis) along with the first alba form recorded for N. "pygmy".

These open from a cupped leaf, have the angular U cleft of form 1 in a notched labellum and at first, sit on the leaf as in form 3 but petiole and peduncle lengthen as the flower matures to look much the same as form 2; hence its separation here into form 5. Is all that clear? The alba form with only faint tinges of pink, looks much the same, structurally and is producing seed capsules this season whereas the normally coloured red one isn't. If the alba seed is viable, this would doubtless be form 6.

Table: Recognition factors (P = present; x = absent)

To winkle out all the differences between N. "pygmy" and the other three from his slides, the
Column first described one candidate taxon in close detail on the word processor then used a
copy of it as a model for describing the next. Every character thus went through the sieve of
close comparison. By the time all 4 tag-named taxa had been through this process, the figurative
fog had mostly cleared.

The Editor wanted more than a brief write-up with some colour pics for any putative new taxa,
so scale factors on slides were calculated from camera settings. Old Bridal Veil Falls shots with
no settings recorded had flowers matched in size with recent shots. From back-projected images, drawings outlined to the same scale, revealed the notable differences in flower size. They were also enough to clear the "fog" for the Column; but what about you the reader? The drawings also highlighted in N. "trijuly" the labellum bib tight against the ovary in the Matakawau specimen yet standing well clear in Barry Lee's kauri bush at Awhitu Central; it's still the same taxon though, isn't it?

Sid Smithies tantalised the Column on 17 Sept 2003 with a cut-away pic of N. "tribaldy" from
Otautau, showing its minuscule column in some detail. The Column had to mock-up a 3-D
microscope from two 20 x lenses and two slides of a cut-away N. "tribrive" to complete the
column sketch herein. He wasn't about to be beaten by a digi camera! Whatever next?

Back projection is okay for the outlines but for details, close examination of the 3-D slides was needed. The two pollinia appear jammed against an inadequate looking rostellum with the anther cap behind and a two winged post anther lobe behind that. The stigma, like a half cup, very close to the pollinia, suffered surgery from the razor blade but this serves to show the tube leading to the ovary.

Incidentally, tribrive's column is different from both the N. "tribaldy" one and the Editor's illustration in J28:11 for the Queenstown N. "pygmy" form 1 (?). Subminiature column detail does not appeal for field ID of N. triloba agg. but with a dissection microscope or macrophotography, identifying characters can easily be discerned in the columns.

Do please have a look at the table and the illustrations. Have you any of these at other locations?
Any information would be gladly swooped upon.