This month’s winner was Jenny Pauley’s photograph of a Corybasincurvus (syn Corysanthesincurva).
Before looking specifically at the species, it might well be worthwhile looking at the features that distinguish the Corysanthes (Toothed Helmet Orchid) group from Corybas (Spurred Helmet Orchid). The major difference appears to be in the flowers. The Corybas flower is dominated by the dorsal sepal which hides the labellum whereas with the Corysanthes the dorsal sepal and labellum are equally prominent although sometimes the dorsal sepal may be the less dominant. A less obvious difference occurs in the leaves. Corysanthes leaves have a fine point but this is absent in Corybas. Based on this only Corysanthes (Toothed Helmet Orchid) occurs in South Australia.
C. incurva, as part of the Corysanthes group, is interesting because the flower does not appear flared or toothed. But though the labellum curves in, it does initially start to flare, and it does have fine short teeth. In fact, in the early stages of the flower opening it can be possible to confuse it with the opening bud of C. diemenica. One of the differences between these two species is that the flower of C. incurva sits on the leaf with no clearly visible stem whilst C. diemenica is raised above the leaf with a visible stem.
This image of a typical Corybas from Colin Rowan, retiredaussie.com , helps to see the difference between Corysanthes and Corybas.
This image of C. diemenica (syn Corybas diemenicus) is a good comparison. Note the difference between the stems.
It’s Christmas and usually, despite Australia’s hot climate, we associate Christmas with snow and cold but we don’t tend to associate them with orchids. And yet, for Australia we do have not one but two Christmas flowering orchids in snow country, that is, on the isolated sub-Antarctic Macquarie Island, an island where “[r]ain and snow are frequent, with only a few days each year with no precipitation”. Admittedly at this time of the year, being summer it is warmer with an average temperature of 7.9degrees Celsius.
The first species was only discovered in 1978 and not recognised as an unique species until 1993 when it was named Corybas dienemus (syn. Nematoceras diemenum). Previously it had been linked with Corybas macranthus.
The second orchid species is Corybas sulcatus (syn. Nematoceras sulcatum) and this species, possibly the world’s rarest orchid, has gone travelling. Staff from the Royal Tasmanian Botanical Gardens have manage to collect and amazingly propagate the seed. Amazingly because orchids, particularly the terrestrial orchids, are difficult to grow. It is now flowering, this Christmas season, but under very carefully controlled conditions in Hobart.
Click here and here to see images and read about this amazing journey.
So Christmas, orchids and snow do go together in Australia, albeit in the far flung island of the south.
Corybas sulcatus (Grooved helmet-orchid) is one of two endemic orchids which occur on Macquarie Island (Photo: Royal Tasmanian Botanical Gardens) Image Source
Certain flowers in large colonies were most popular over several days and both sexes were observed feeding on the boss, which suggests a food-related attraction. Virtually nothing was known about the Corybas pollinators and primary literature to date only offered hypotheses. Based on our findings, the persisting statement in literature that ‘Corybas species attract fungus-gnats as putative brood-sites’ is incorrect for the taxa in Victoria. No evidence of ovipositing in flowers was found. Females feeding looked gravid and were presumed to be unfertilised. All individuals looked fresh with undamaged wings and it was apparent they had recently hatched.
Is this a hypotheses that needs revising? Rudie definitely demonstrates the importance of careful and meticulous observations.
July is Helmet Orchid Season; and the theme for the July Picture Competition.
In Australia, the genus Corybas in the broad sense (sensu lato) has four segregate genera; three on the Australian mainland (Corybas, Corysanthes & Anzybas) and one (Nematoceras) on Macquarie Island. All three mainland segregate genera were represented this month. Robert Lawrence’s, Anzybas unguiculatus; Margaret Lee, Corybas aconitiflorus with Jane Higgs, Lorraine Badger and John Fennell all entering Corysanthes diemenica. Lorraine also entered Corysanthes despectans; and John an image of Corysanthes incurva. The clear winner was Jane Higgs’ Corysanthes diemenica (synonym Corybas diemenicus).
The flower of Corybassensu lato is characterised by a large dominant dorsal sepal and an equally dominant labellum. The other features associated with an orchid are not so obvious. The column is short and not visible. Even the ovary is barely visible whilst the other petals and sepals are but short thin filaments near the ovary. The base of the labellum wraps around to form a tube which hides the column; and the upper portion of the labellum folds back on itself and flares out. With this structure, two new features are introduced, the boss in the centre of the labellum and the auricles, two earlike openings formed from folding at the base of the labellum. Two growth features that are different from many other orchids are that the bud and leaf grow concurrently and once pollination has occurred the stem elongates so that the ovary can be raised up to 20 to 30 cms, thus allowing for seed dispersal.
Jane’s picture clearly shows these features as in the labelled image below.
Thank you to Greg Steenbeeke for reviewing this article.
Reference
Backhouse, G, et al (2016) Bush Gems: A Guide to the Wild Orchids of Victoria Electronic version
Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA
Jones, D. L., A Complete Guide to Native Orchids of Australia Including the Island Territories. Reed New Holland
Jones, D. L.; Hopely, T; Duffy, S. M.; Richards, K. J.; Clements, M. A and Zhang X, Australian Orchid Genera an information and identification system. Electronic version, 2006, CSIRO
Rules of entry:
The subject matter must have something to do with Australian orchids. Any format is acceptable including Photo shopped images, artwork, etc
Anzybas unguiculatas (common name Little Pelican or Cherry Helmet Orchid) was the main focus for this month’s competition with three photographs of this diminutive flower.
The other photographs were Ed Lowrey’s close-up of a triggered Urochilus sanguineus labellum, John Badger’s first Diuris palustris sighting for this year and Pauline Meyer’s mass flowering of Leptoceras menziesii post fire. Of the Anzybas, Jenny Pauley entered two and Lorraine Badger one. Jenny Pauley’s photograph of two flowers was the outstanding winner.
Originally named Corysanthes unguiculata (1810), then Corybas unguiculatus (1871), the genus name was changed in 2002 to Anzybas in recognition of its distribution both in Australia in New Zealand. Since 1945 it had been recognised that the New Zealand species Corybas cheesemanii was a synonym for Corybas unguiculatas although the juvenile plant can have two leaves unlike the Australian species which is single leafed.
An interesting feature of this flower is the prominent white ears at the rear of the helmet (not clearly seen in this photograph) which are part of the labellum.
These plants are small. The gum leaves and twigs give an idea of size but the engagement ring shows it very clearly. Note also the prominent ‘white ears’ of the labellum.
An unusual aspect of this photograph is that the colour of the underside of one of the leaves. It lacks the characteristic distinguishing feature of the purple underside of the leaves. According to orchid growers, the light affects the leaf colour. Heavy shade produces green leaves. It is possible that the heavy leaf litter where this plant was growing provided enough deep shade to cause the colour loss.
Bates (1990) states that it (has) not proved amenable to cultivation, but it has, on rare occasions, been benched at NOSSA meetings with the most recent occurrence was in July 2010 but it remains a very difficult plant to cultivate. The electronic version Vol 34 No 7 has a photograph of the plant just visible within the moss.
It is not always easy to photograph this species as not only is it rare with limited numbers but there are very few sites where it can be found. Added to that is that the window of opportunity is short in South Australia with a flowering time from June to August compared with those interstate which can range from May to October.
There has always been an interest in Australian orchids. Over the years there have been many photographs of orchids. This stereographic postcard from 1928 is a study in beauty –
This postcard is held by the State Library of Victoria.
Although the distribution covers the Southern Lofty, Kangaroo Island and the South East regions of South Australia, it has become increasingly rare due to loss of habitat which consists of leaf litter on damp soils. As a result, there are very limited localities where they can now be found.
It is one of our earliest helmets to flower which is from June to July.
Rupp, HMR and Hatch, ED (1945) Relation of the Orchid Flora of Australia to that of New Zealand in Proceeding of the Linnean Society of New South Wales Vol 70 1945, pages 53 – 61
If you want to see the Helmet Orchids, now it the time of year to find them. My understanding is that the time from leaf mergence to capsule is about six weeks. In the past week I’ve seen Corysanthes diemenica (Veined Helmet Orchid) both in the north and the south of the Adelaide Hills. Corysanthes incurva ( Slaty Helmet Orchid) appears slightly later, end July early August, and will now be in bud. Look for them amongst the leaf litter.
NOSSA 