Journal Number 103
May 2007

ORIGINAL PAPERS

Caladenia's at Awhitu
By Tricia Aspen

Prior to the 2004 season the only Caladenia species noted for the Awhitu District was the little C. chlorostyla and a pink flowered one found in the middle of a clay track on "Suite Ridge" in Lee's bush on 20 October 2003 which I was unsure about.

This latter one was a definite pink with rounded petals and I tried to identify it by using the pictures and descriptions in the "Field guide to the New Zealand orchids". I concluded C. bartlettii and a phone call to Eric Scanlen convinced me that it was so.

That is until the following season when a visit from Eric and Allan Ducker on 12 October 2004 found none open enough to make definite identification. That small colony and one nearby was given the probable diagnosis of C. aff. pusilla.

A single flower was observed in the nearby "probable C. aff. pusilla" colony a week later and I lumped
the C. bartlettii in with that lot. On 19 October Eric photographed and confirmed that C. aff. pusilla it
is in the easternmost colony on "Suite Ridge" (Fig.11).

In 2005 flowers were either nipped off or missed. In 2006 the tiny colony had one flower out on 17 October. The marked rounded petals which were not up-turned niggled in the back of my mind.
A photograph sent to Eric has confirmed it as C. bartlettii s.s. (Fig.10).  

During the 2004 visit from Eric and Allan another colony on "Romney Ridge" was noted as having a slightly different looking one. They put it as "maybe C. 'nitida rosea'" as we were unable to catch it open.

In 2005 I almost struck it right but the other taller one on "Romney Ridge" was missed again and would you believe it, I missed it yet again in 2006 even though the two other Caladenia colonies on "Suite Ridge" still had flowers on 15 October.

I was busy drooling over the orchids in Western Australia at the time when the elusive one was open! The Australian Orienteering championships lure us almost every year and despite virtually jumping off the plane on return and rushing off to try and catch the maybe "nitida rosea" in flower I have always been too late.

These little orchids are quite specific with flowering times. C. bartlettii s.s. and C. aff. pusilla
flower at Awhitu in first three weeks of October.  

A foray into Dodd's bush off Boiler Gully Road in mid-November 2005 saw the discovery of a different looking Caladenia. Flowers had just closed up on the two plants under kauri on an exposed ridge but there was reddish maroon on the sterns and backs of the dorsal sepals and both had two flowers per stern.

Keen to catch it I visited on 25 October 2006 just to find buds forming. However I couldn't help noticing the Pterostylis banksii flowering in abundance all around so the day was not without satisfaction. A return on 1 November and two were open and seven in bud.

The colour is quite different from any others I have seen (Fig.12). A delicate mauve and the petals are pointed, not at all like the rounded ones of C. aff. pusilla. Then again the petals are upturned and the dorsal sepal lies tightly on to the column, similarities with C. aff. pusilla. Column wings are the same lime green as the dorsal sepal of C. chlorostyla which come into flower some three weeks later. It is possible that we have a hybrid here.

Plants have a single leaf about 15cm long, somewhat hairy and the same length as the hairy stem. Most of the nine in the little colony covering a narrow eight square metres or so had two flowers per stem.
All had finished by 11 November.

I have tagged this C. "kauri mauve" for the time being and in spite of searching likely sites have been
unable to find more of the same. C. "kauri mauve" has been observed to flower between the last week
of October and the first two weeks of November.  

Orchid hunts in new territory did turn up two more large colonies of C. chlorostyla [C. minor,
J 99, 22].

I had revisited the Kemp Road colony on 11 November to compare flowering times with C'. "kauri
mauve". Plants were just emerging and starting to form buds. Even so it was obvious at that early
stage that most were going to carry multi heads.

A later visit on 27 November showed only around 60 plants present for 2006 compared to about 200 the previous year and only one four flowered stem. A delight was one plant with three flowers out at once (Fig.13). This specimen was 27cm tall, the single leaf 21cm long and there was a bract of 15mm halfway up the stem between the ground and the base of the first flower. A very faint sweet perfume could be detected.

These plants are much taller than the original little C. chlorostyla discovered in earlier years in sheltered positions under manuka and on the side of clay tracks in Lee's bush. Flowering times are
the same and an occasional two-flowered stem had been observed. Can sites cause such variation?

The second site for the multi flowered ones is at Shepherd's off Boiler Gully Road about 4.5km from Kemp Road in a straight line. Again the site is exposed to the near constant southwesterlies and under kauri with many plants (100+) spread over a gently sloping broad area of around 100 square metres. On 13 November most here were carrying two flowers per stem and many had three. Very few had one flower.

The third site found on the same day is at Roycroft's in steep kauri country. Around 3km from Kemp Road, yet again the site is exposed, this time on a narrow spur overlooking the gully leading out to Irwin's Gap on the west coast. It was a great lunch spot under medium sized kauri amid a colony of around 30 green and white Caladenia's. I would expect there to be more in this area but time prevented further looking. The multi flowered C. chlorostyla flowers from the second week of November through to mid-December.

All three sites have in common the fact that they are exposed to the southwesterly winds, are under kauri in fairly heavy litter where one would expect to find Pterostylis agathicola (of which there is no sign) have large numbers of two, three and occasionally one or four flowered stems.
The dead mingimingi at Kemp Road does not feature at the other sites.

It is most interesting to read HB Matthews' letter, from Kaitaia on 17 November 1912, to TF Cheeseman (Matthews and Son on Orchids, pg 53) where his green-white Caladenia often showed four buds and sometimes had three flowers out at once.