Journal Number 88
September 2003

THE COLUMN

Move Your Feet - Do Take Steps In Orchid ID
By Eric Scanlen

The esteemed writer (Bruce Irwin) of 'Let us keep our feet on the ground' [J87:28] knows full well
the Column's penchant for healthy debate and knows that such an open challenge could not go unanswered.

Tagging
The Column is unrepentant about encouraging people to tag their colonies of unusual taxa which are seed propagating, not including the solitary mutants or sterile mutant colonies that spread vegetatively. Keeping one's feet on the ground is one thing; staying rooted to the spot is another.

If we are going to see advances in our orchid taxonomy, one has to step out. Do please announce your unusual taxa to the Journal, with a tag so that others have a handle with which to associate their own finds and thus establish the limits of their territories. If you hang back, your orchid may get lost in anonymity.

Take for instance Nwsltr 5:1, Dot Cooper's Gastrodia from the Puffer Track, 15 Jan 83, fawn with white petals and a short column. It got indexed as "G. cunninghamii albino" along with Fairlie Horsley's (Nwsltr 30:1) "G. cunninghamii. . . lovely pale cream in colour" from NW Nelson and with Ian St George's [J72:32] "pale green, short columned ... Gastrodia" from Paradise (the places that man's been!) and Queenstown. Not a tag amongst the three of them! although Ian wondered about an unlikely connection with G. leucopetala (Col).

Now Mr Kelly Rennell [J87:26] has sent in some brilliant shots from Lake Hauroko's shore, of that same Paradise taxon. Note the distinctive saddle shape; the green shade of Ian's could well be available-light problems under green canopy. So Kelly scooped the pool by tagging it (pers. comm.) Gastrodia "shauroko" short for "Short column Hauroko" and the Column belatedly made the connection with the wrongly indexed "G. cunninghamii albino": to be corrected. I do hope Dorothy's and Fairlie's specimens had those distinctive, non-cunninghamii, abrupt saddle and turned up orange labellum tip because they will all now get re-indexed under G. "shauroko".

What if formal analysis shows this form little different from G. cunninghamii? No big deal - but unless we ask the question, how will we find the answer?

Who else has spotted this taxon and said nought in case they got made fun of? Remember, these are not impossibilities like flying saucers! There are 70++ unnamed taxa in NZ (not counting a range of Pterostylis aff. montana and hybrid swarms) according to the collected list from the Journals index. If you have one or another, do tell the readers of the Journal about it and if it appears distinct tag it!

Does it really matter whether such as P. "brumobula" [J80:18-20] are actually separate taxa?
The question should at least be asked, and the Column still needs more info on this one. Bruce could well have used for an example of unfortunate tagging his own Corybas "ratty" which has yet to have its obituary written in the Journal. It turned out to be Nematoceras "whiskers" which itself had been found and described in manuscript by Henry Matthews about 1928 as Corysanthes "viridis". So by rights and tagging lore, we should be calling it Nematoceras "viridis", shouldn't we?

Sheathing bracts
Bruce brought some useful traits to notice re the sheathing bract (SB) on Nematoceras iridescens.
Quite similar to N. acuminata (J85:141 it would seem. The Column also noted that the SB position
in N. acuminata was usually 5-6mm above the tuber but was also unrelated to its distance from
the leaf axil. N. macrantha too, as Bruce pointed out, has a variable stem length from SB to leaf axil.
The colurmn's shot of N. macrantha on a bank with leaf axil right at the SB confirms.

However the shape, size and colour of the SB are traits worthy of notice and in N. triloba taxa particularly, the SB may be a clear identifier in such as N. hypogaea (Col) and N. "pygmy" where the leaf axil is typically right at or inside the SB. For instance, the photos on the right, N. "trijuly". The Column is red-faced at having these slides masquerading as N. "pygmy" until recently. N. "trijuly" plants look similar to those of N. "pygmy" but they can't be the same; the leaf axil is 5mm or more above the SB, it has a long petiole and its flowering peak is a month later. Physical traits are sorely needed to separate the multiple taxa in N. triloba so please do not cast aside the handy SB just yet. Colenso first wrote about it, even though subsequent chroniclers have chosen to ignore it.

Colour
Bruce's concern that we should not differentiate taxa on "inconsequential differences" like colour, is a convention stemming from pressed specimens eventually turning brown so colour is not much use for IDs from herbarium specimens. Botanists could be leaning too hard on the all-important pressed specimens in this respect.

In the field, orchidologists can find colour differences in fresh specimens to be a valuable signal and sometimes a clear identifier. For instance the cerise shade of Petalochilus bartlettii and the redder P. aff. fuscatus (more correctly, P. "nitida rosea" ex Matthews) detected at Scott Point [J82:7] made ID possible from 2m away.

But care is needed for Thelymitra and others which diffuse their colour just before opening. T. aff. ixioides and its amphidiploid off-shoot, T. nervosa, are notorious for this as the Column found when translocating the latter to the Iwitahi Reserve. Almost all the buds which were opened for ID had white tepals but with dark spots already formed. Some, such as Chiloglottis valida, open green but diffuse their colour well after the flower has opened to become that deep purplish shade which confused Bruce. Dorsal sepals on Nematoceras triloba agg. often do the same.

Beware film colour though. Slides are better than the prints which often get "corrected" with filters but all films can get confused in the violet, purple or mauve shades. E.g. compare or more likely, contrast J62:12 (T. aff. longifolia to the Column then) lilac, from a slide and J62:25 (T. nuda was the Editor's thought) pink, from a print of the same flower taken earlier in the day, tagged incidentally, as T. aff. longifolia "tired one" (as per index) by Bruce from two plants side-by-side.

Conclusions
1. Take note of the sheathing bract's characters especially in N. triloba agg.
2. Colour can be a useful identifier in the field but can be misleading on photos lacking a colour
     chart or in the violet/ purple range with or without a colour chart.
3. Get someone involved to proof-read your draft write-ups.
4. By all means identify unusual seed--propagating colonies with a tag and do tell us about them.
5. Nematoceras "trijuly" stands as a valid taxon in the Column's book.