Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Sunday, November 04, 2007

A new Greenhood - for me - on Tourist Road

A week ago, I led a group of Orchid enthusiasts along Tourist Road, East Kangaloon to look at the varieties of Ground Orchids there. (That was before the SCA slashed the heads off all those plants.)

Anyway, Graeme Bradburn of the Illawarra Branch of the Australasian Native Orchid Society was the first in the group to spot a Greenhood Orchid growing in a shallow drainage trench running between the road and the bushland. We all had a look at this plant, and some debate followed as to which species it might be.Alan Stephenson (also of ANOS Illawarra) suggested that it might be a particular plant described as a "naturally occurring hybrid" - Pterostylis x ingens (which is classed as a "naturally occurring hybrid"). Other names were also suggested, but we took lots of photos and agreed to go home and check our reference books. Subsequently, it was suggested that the plant might be Pterostylis monticola. I have checked the standard reference books, but this plant does not seem to match the leaf form described for that species.
Ptst. x ingens was once classed as Ptst. acuminata, but that plant is an autumn flowerer. Ptst. x ingens is said to be a naturally occurring hybrid between Ptst. nutans and Ptst. falcata.Alan came back up from the coast, for another purpose last Friday, and he and I went back to this site, and found 4 more of these plants growing, 2 with good flowers. All were in the same shallow drainage channel. We took more photos.

Incidentally, these plants were not slashed, as they are in a trench, where the slashers could not reach. Thank heavens.
It seems from checking other Orchid reference sites (which are listed on the right hand side of this blog) that this plant is found in Victoria, and is know as Pterostylis x ingens. But it appears there are 2 different plants known by this name. One has a much more bent over flower, with a rough (hairy) Labellum, and a recurved tip of the dorsal sepal. Check on Click on the "Orchid 3" page, look for "large-pointed Greenhood", then click on the photo to enlarge, and then go to "both forms". (Sorry, but it is not easy to find). Then go to Colin Rowan's "Retired Aussies" website, and click on his "latest additions" page, and look for Pterostylis x ingens (added 17 August) to see what I mean about the 2 different plants known by this name.
Conclusion? I am going to stick with Pterostylis x ingens (?). I will keep the question mark - until I hear differently.
Cropped photo showing the "labellum"
and also the pollinia still in position, up inside the "hood" of the flower.
I think the taxonomist need to keep working on this plant, for there seem to be two different plants known by the same name. Also, I think the classification as a "naturally occurring hybrid" is ambiguous, to say the least, as there appear to be many widely dispersed plants of similar form, (which to me implies a genetic stability, not what one would expect from a "hybrid"), and yet there are these other plants, (of an equally stable, yet distinctive form) - which I think would mean that these plants are both true species, and that each warrants a different name.

Incidentally, a Google Image search reveals a photo of this same variety of plant from a collection of a Japanese Orchid Collector. Clearly this plant has been collected from the wild, at some stage, and sold overseas.
I am not going to comment further on the issues which that raises!


Gaye from the Hunter said...

Extremely interesting observations, Denis, which I will keep in mind if I find a similar species during my wanders in the Hunter Valley. Thank you for sharing your find along with associated information and links.


Denis Wilson said...

Hi Gaye

I wasted several hours yesterday, searching other similar drainage channels running under the road, and crossing into the catchment. Not a sign of any other Greenhoods.

I was a bit nervous, looking for Red-bellied Black Snakes, but found a young Water Dragon instead.