Journal Number 112
May 2009

ORIGINAL PAPERS

Yet Another Imbroglio
By Bruce Irwin, Tauranga

Caladenia minor

I didn't know what an imbroglio was until I read Eric Scanlen's "The Caladenia minor imbroglio" in NOG Journal 72.

Do we really need imbroglios? Provided each new species is described accurately and adequately, imbroglios should not occur. But remember the difficulties Hooker and his associates faced.
The plant they were dealing with may have been the first of its genus to be described.

How could they know what characters would be important in their description, to ensure the plant in hand could not be confused with others of the genus, yet to be discovered?

While the early botanists struggled to catalogue the New Zealand flora, rules governing taxonomy and nomenclature evolved simultaneously. Some unworthy amendments to the rules of nomenclature were made to ensure that the first legitimate name applied to a plant was preserved.

Scanlen's Caladenia minor imbroglio reveals that most specimens on its so-called "type" sheets were actually the plant we now know as Caladenia alata. However, that plant had already been legitimately described by Robert Brown: possibly not clearly enough, because Hooker in Flora of Tasmania Pt 2 published as C. alata an illustration of a quite different species showing four rows of laminal calli on the labellum.

Incidentally, his illustration of Caladenia carnea in the same volume was certainly not of that species. Even the great Hooker made mistakes, in this case a bunch of them.

Strangely, in Australia, Brown's C. alata was misunderstood almost since its description in 1810, as was Hooker's C. minor in New Zealand since 1853. This confusion continued until 1987 when Australians at last recognised that the plant Brown described as C. alata, was the plant which NZ botanists at that time called C. exigua.

How wonderful! names could settle down. However, that did not happen. The C. minor imbroglio "blossomed".

Misguided attempts were made to perpetuate the name C. minor. Caladenia chlorostyla thought to be present on Hooker's so-called "type" sheets was promoted as C. minor. How illogical!
About the only character likely to be of use in Hooker's description of C. minor was that it was pink. C. chlorostyla is green, in leaf, stem, ovary and tepals.

The name C. minor was redundant and should have been regarded as invalid, thus allowing those specimens other than C. alata on Hooker's sheets to be named and described in due course.

No, we don't need imbroglios!

Prasophyllum colensoi

The imbroglio I am about to introduce concerns Prasophyllum colensoi J.D. Hook Fl. N.Z. 1, 1853, 241 Type Northern and Middle Islands, common, East Coast and interior W. Colenso; Canterbury D. Lyall. No holotype was selected, but according to M. Clements, syntypes are held at Kew (possibly including specimens from both Colenso and Lyall).

Hopefully those syntypes are all of a single species, but is it possible to be sure?

I don't think so. Flowers of most Prasophyllum species are so small and so alike, that I would be reluctant to attempt identification from pressed specimens. Fresh flowers are quite difficult enough.

For many years it was suspected that P. colensoi was identical with the Australian P. alpinum, so in 1996 David Jones published "Resolution of the Prasophyllum alpinum complex in mainland south-eastern Australia, Tasmania and New Zealand" [Muelleria 9: 51­62 (1996)].

In that paper I was informed that P. colensoi could be distinguished from P. alpinum by the column wings being as long or longer than the anther. How distressing! All drawings I had made of P. colensoi show a very short column wing barely half the length of the column.
Had I been wrong in my identification of the plant drawn?

No, not likely. One of these drawings had been prepared to illustrate Flora II, and Dr Lucy Moore had approved it. Also, Hooker's original description of P. colensoi in Flora Novae Zelandiae stated, "Column very short, with very low 2­lobed lateral pieces". In no way does that suggest lateral lobes equal anther.

In searching for an explanation, I found that David Jones's illustration of P. colensoi in the paper was of a plant from Lake Lyndon in Canterbury, one of the ten mentioned under the heading SPECIMENS EXAMINED. It may have been the only specimen received in fresh flower, in which case it would have influenced Jones's description of P. colensoi.

Since then I have examined carefully all Prasophyllum flowers found, always finding that the column wing was barely half anther height, until Anne Fraser drew my attention to a purple-stemmed Prasophyllum from the up-mountain road above Ohakune. All flowers on this plant had column wings almost as long as the anther and the tepals all carried quite prominent purplish streaks along their mid­lines. Flowers of P. colensoi (as I understand it) may vary from yellowish green to reddish or purplish green but all parts of the plant, leaf, stem, flower and ovary are one unvarying colour.

We coined the tagname Prasophyllum "A" for the P. colensoi look-alike, later finding that the striking dark purplish stem was not constant and that the plant colours varied from yellow green to reddish green to red and almost to purplish black. Some even mimic P. colensoi, though the purplish striping along tepal midlines seems constant.

Having realised the distinctiveness of Prasophyllum "A" we hurried down to Middle Road just south of Horopito where we had observed a taller Prasophyllum on which flowers were somewhat bi-coloured, a little larger and with longer slimmer tepals. This plant showed a minor structural difference. The floral bracts were tapered, not truncated as in Prasophyllum "A" and P. colensoi and the plant favoured very wet conditions even growing in shallow permanent water. This form which we tag named Prasophyllum "B" has been found at Pureora and near Tauranga. It may be wide­spread. The Lake Lyndon plant sent to Jones may be Prasophyllum "A" or "B" or even a third form.

I have just returned from the NOG weekend at Camp Wakarara in the eastern foothills of the Ruahine range (Colenso's country). I hoped that we might find Prasophyllum "A" or "B" as well as P. colensoi during the weekend.

On the Saturday evening (6 Dec 08), Mary Watson told me she had seen a purple-stemmed Prasophyllum high on a minor peak, beyond the point I had reached. Her husband was less sure the stem was purple, but showed me digital images in his camera. Stems were barely evident but flowers showed purplish streaking. They looked like Prasophyllum "A" and probably were.

The trip planned for the next morning was allegedly on a short almost flat track beyond the Waipawa river. We found the track neither short nor flattish, but to my delight we did find Prasophyllum "A" in good numbers. Most had deep purple stems, just as above Ohakune,
but a few smaller plants were green-stemmed.

If P. colensoi was present I didn't see it, though at first I thought the green stemmed plant might be it. Where else will these unnamed Prasophylla be found? and what other forms may await discovery in South Island mountains?

Had David Jones suspected that one or more Prasophyllum colensoi look-alikes existed, his "Resolution of the Prasophyllum alpinum complex..." would have been just that - a resolution rather than a muddying of the waters.

Now, I make a plea to some keen young botanist to determine what P. colensoi look-alikes exist throughout New Zealand, map their distributions, then publish valid descriptions.