Journal Number 88
September 2003


THE COLUMN

Pterostylis Round-Up
By Eric Scanlen


1
. Pterostylis irsoniana stole the show at Gordon Sylvester's Blue Creek, Kahurangi National Park on 25 Nov 02 for signal red and white stripes (Photo right).

The colour in these and others that Gloria and the Column met at L. Kaniere, Hokitika Gorge and Takaka Hill, leave his Egmont ones for dead.

 
Pterostylis irsoniana
     

2. P oliveri at Blue Creek all sported the spiral dorsal sepal which curls through 270 (Photo lower- right).

But those from the type locality at Arthur's Pass on 7 Dec 02 had the more elegant but rarer, recurved dorsal sepal
(Photo upper-right) usually depicted in the literature.

 
Pterostylis oliveri
Pterostylis oliveri
     

3. CHS Takaka Hill, on a fine 26 Nov 02, took the cake for fine vistas around Nelson so, the Tackle-Anything-Trio (TAT), Mark Moorhouse, Gordon Sylvester (Puddy TAT?) and the Column, sought instead the bush and blocky limestone at Hawkes Lookout - thanks for the tip Graeme Jane - and took a figurative bath in a multitude of the promised green-hoods.

P irwinii in red livery (Photo top-right) still unfurling, was here.
It was also scattered around St Arnaud, previously unreported,
in ER 49.

A stumpy P. australis? with an elongated galea and hump-backed dorsal sepal (Photo middle-right) took the TAT's attention, In the open or light shade, the hump-back was particularly noticeable, the labellum was red (also red in Aorangi SFP, Ed.) but with the typical tiny arch in the tip margin.

But in deeper shade, P australis (Photo lower-right) reverted to more normal dimensions and dark brown labellum tip. The TAT consensus (but not conviction) was that the stumpiness, which occurs in other greenhoods, resulted from exposure.

Spent P banksii and a red stemmed P. irsoniana also came to
light at Hawkes Lookout.

 

Pterostylis irwinii
Pterostylis australis
Pterostylis australis

 

4. At least 4 species, in Nelson, have been first spotted around Mt Egmont and/or the Central Plateau.
(Pt. irsoniana, irwinii, Nematoceras "Sphagnum", and N. "round leaf") where they are isolated to patchy.
What does this prove?

  1. A. Bruce Irwin who had a hand in all four in their limited N.I. sites, is a top species spotter.

  2. Orchid species spotting has been so conservative around Nelson (e.g. Jean Jenks told of an odd
    "Pt, graminea" reported by Brian Molloy at Harwards Lookout and sent Allan Ducker and the
    Column looking for it on 10/11/99. It was Pt. irwinii [1] which Allan recognised immediately, J70:36)

  3. Nelson species were quick to blow north as seed to colonise areas devastated by volcanism,
    Graham Dickson J70:40]. Central Plateau plant life was obliterated by the cataclysmic Taupo
    eruption of A.D. 200 [2] so where else could those 4 species have come from but Nelson?
    Curiously, most of the 4 migrant species have remained localised in the north, possibly because
    of subsequent competition from other species recolonising the volcanic desert 1800 years ago.

 

5. Gloria and the Column met Thom Pendrigh and Hazel at Lake Lyndon on 2 Dec 02. Thom knew the minuscule Hymenochilus tristis (was misnamed Pterostylis mutica) from Oxford's View Hill Reserve but no amount of crawling nose-to-turf had disclosed any this season so they had been pleased to meet here to check on others' finds.

The site, carpeted in that high country plague, Hieracium pillosa, looked unlikely but Thom was undeterred and triumphed near the cattle stop. A colony of tiny spikes peeped through the Hieracium in a 5m² area. Photo upper-right shows a 62mm tall plant, after moving the Hieracium and a worm cast, covering the complete basal rosette! Next Hazel spotted a solitary, all-green specimen (Photo middle-right).

Thom had his lens out and declared both to have the basal appendage on the labellum pointing inwards so both green and brown forms were H. tristis. Possibly, the "Hymenochilus tanypodus" (was Pterostylis aff. cycnocephala) which had been previously reported flowering in November was actually this green form of H. tristis. The Column's pics don't show the all important appendage do they? But Photo below-right shows minute denticulation to the petal margin, as described by Moore & Edgar in Flora II and as drawn by Bruce in the Field Guide. The flowering time was also right for this subalpine site.

Later (22 Dec 02) the TAT and others hunted the Rainbow Skifield, above any Hieracium and still failed to spot H. tanypodus with its entirely smooth petal margins and forward facing basal appendage to the labellum.

 

Hymenochilus tristis
Hymenochilus tristis
Hymenochilus tristis
     

6. The Column needed P. areolata but the TAT found neither it nor
P. porrecta along the Hackett Track on 28 Nov 02. But Thom knew of some in a location near Oxford.

P. areolata in the open on 2 Dec 02 were stumpy, as Pterostylis
can be but some of average height in the shade were nicely
figured in red (Photo right). Many thanks to Thom and Hazel
for donating valuable time to the cause.

 
Pterostylis areolata
     

7. Dan Hatch's holotype of P. montana at CHR on 10 Dec 02
(Photo lower-right) in transmitted light, shows the column and labellum in silhouette, but column wings and labellum basal appendage seem to have shrivelled, sad to say. However, the straight, flat, lateral sepals etc. define it well enough to confirm Mark's identification of a specimen near St Arnaud on 22 Dec 02 (Photo upper-right).

This solitary specimen could have been Dan's model for the description drawing, [J72 p36] right down to the 2 short, acute, bracts at the base. Notice that the labellum is "green, recurved, the tip unevenly constricted" as Dan described. This aligns uneasily, if you study the evidence, with the sensu Moore taxon [J25 p13 from Otago; J71 p20 from the Central Plateau] where the labellum usually twists 90 to the right and the lateral sepals curl at the tips; up to 360.

Mr Kelly Rennell sent a CD from the far south with 4 pics of P. montana also with straight flat sepals and Mark revealed other colonies in Big Bush State Forest, off Station Ck, ER49. Kendyll and Caryl Moorhouse helped in the hunt at Big Bush and were intrigued with the in-bud Gastrodia cunninghamii colonies and a friendly S.I. Robin.

 

Pterostylis montana

Pterostylis montana

     

8. P. graminea "red coil" at Tophouse Reserve, ER49, has to be seen to be believed (Photo right).

Mark took the TAT there on 29 Nov 02, to colonies of this long leafed taxon under beech forest.

 
Pterostylis graminea

 

Pterostylis peninsula9. P. "peninsula" Gordon's new taxon from the Brunner Peninsula, St Arnaud, has a
flower akin to P. cernua but longer leaves more like P. graminea. Gordon spotted a colony
of several diminutive specimens by the driveway to Dennis Meade's bach and tagged them
P. "Peninsula" in J86:29.

The Column had searched in vain at the wrong culverts near Kumara for P. cernua and this looked like it. Brian Molloy scuttled that idea on the email by indicating the different leaves.

The diminutive stature of Gordon's "type" P. "peninsula" has to result from exposure. A nearby tight colony of 55 flowers, of more respectable height and one filmed(Photo right) on the Peninsula Nature Walk (North Islander slack spotting!) were more typical of a considerable population here. The sepal plate at right angles to an orange-striped ovary, a blackish labellum plus dorsal sepal and petal tips coinciding, said P. cernua but minor things such as a dusky red apiculus, at the labellum tip and labellum appendage forked instead of 11 fingered also gave subtle indication of a separate taxon.

Others on that Walk were P. graminea s.s.; "Habit of P. Banksii but smaller and much more slender" as Cheeseman described it in the 1925 Manual.


10
. Mark took the TAT over to Kerr Bay camping ground at Lake Rotoiti and along Black Birch Creek, through
a bewildering plethora of greenhoods, all in flower on 22 Dec 02. There were Pterostylis "peninsula", graminea, irsoniana, irwinii, montana, aff. montana, and every hybrid imaginable between them. So mark St Arnaud as a prime GLOS (great little orchid spot).


11
. Prime P. banksii s.s. on 4 Dec 02, with long turned up dorsal sepals, occurred by the path to the white heron and royal spoonbill sanctuary, Waitangiroto River. One of the foreign tourists actually lay down on the board-walk to photograph one. How embarrassing? The Column would have joined him but he was economising on film.

The number of clean flowers in the open was surprising as was a kie-kie (Freycinetia banksii) flower or tawhara, wide open and unmarked. Both are normally dessert for 'possums and/or rats. Our knowledgeable guide put its survival down to the determined clearance of predators from the region for the benefit of the birds. So, the orchids and other plants are also benefiting from the spin-off. Later, Kelly's CD depicted prime P. banksii from the far south confirming its NZ-wide status.


References

1. Jones, DL et al, Six new species of Pterostylis R.Br. from NZ, The Orchadian Vol. 12, No. 6:266.
2. Hicks, G. Campbell, H. Awesome Forces Te Papa Press, Wellington, 1999.

 

 

 

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