With two sun orchids entered this month it is not surprising that one of them should be the winner which was John Fennell’s Thelymitra azurea a lovely blue flower with hints of pink. The other sun orchid taken by Pauline Meyers was one of the lovely pinks, T. rubra. She also entered a picture of Pyrorchis nigricans with a spider quietly waiting for its next meal! The final entry from Trevor Williams was that of a double headed Diplodium robustum which he found at Spring Gully Conservation Park.
An advantage of entering a photograph is that it does not need to be in season. This month John Fennell entered an autumn flowering Corunastylis fuscoviride and a late spring/early summer flowering Diuris sulpherea, Robert and Rosalie Lawrence both entered the winter flowering Diplodium robustum and the winning picture, John Badger’s Thelymitra epipactoides is an early spring flowering orchid.
Sun Orchids are another popular winner of the competitions and as there was a comprehensive article written on Thelymitra epipactiodes and as some have asked “what, actually, is a sun orchid?”, it is time to answer the general question about Sun Orchids.
Of all the Australian terrestrial orchids Thelymitra or Sun Orchid is the one that looks the least like an orchid as all the segments – the sepals and petals including the labellum – are very similar in appearance. They mimic the flowers of the Lilliaceae and Goodeniaceae families.
Nevertheless, it is an orchid as evidenced by the column. Columns are a unique feature of orchids. They are the combination of the reproductive organs into one structure. Between the different Thelymitra species, it is the column that is often the main distinguishing feature used in identification. Because, the column is quite detailed and so important in identification, we plan to feature this in future Journals.
Other general features of Thelymitra are single, non-hairy, mainly linear leaf (of course, there are always exceptions) with a single flower stem. Flowers range from being singular to having multiple flowers which come in a range of colours from yellow to pinks to blues. Despite the lack of nectar, most Thelymitra are bee pollinated but there are some that are self-pollinated. The pollinia instead of being yellow are white and it is not unusual to see the white pollen on the self-pollinating flowers.
Reference
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
Thelymitra https://en.wikipedia.org/wiki/Thelymitra Accessed 4 July 2018
One never knows what species will be entered each month – this month’s entries included Andrew Primer’s Eriochilus collinus, John Fennell’s Prasophyllum elatum, Marg Paech’s Pterostylis nutans and the winning picture, Pauline Meyer’s Arachnorchis sp. (which has subsequently been identified as Arachnorchis sp.)
In the last six years there have been over a dozen photo competition articles (the most recent April 2018) written on some aspects related to Spider Orchids. So, with another Spider Orchid winning the competition it is about time to answer the question – What Is A Spider Orchid?
Around the world, the common name Spider Orchid has been bestowed upon a number of orchids in different genera. In Australia, they have principally been applied to a large group within the genus Caladenia, a highly diverse cumbersome genus.
Caladenia in the broad sense is distinguished by erect flower stem and single linear, ovate to lanceolate leaf, (both hairy), labellum distinctly different from the other segments, generally fringed, curved and decorative calli. But within this genus it has been recognised for a long time that there are several distinct but varied groups, which has been reflected in the common names – Dragon, Pink Fingers, Hare, Spider, Wispy Spider, etc.
Consequently in 2001, several segregate genera were published including Arachnorchis for the common named Spider Orchids. This was not widely accepted, as reflected by the Herbaria of Australia. Indeed the original authors are no longer using the segregate names.
Yet despite all that, the segregate names have proved to be very practical for fieldwork. By using the segregate name when species is unknown, extra information is communicated. This was the case with Pauline’s picture. Yes she photographed a Caladenia but which one? It was an Arachnorchis species.
With that in mind, it is time to consider the features that make up a Spider Orchid or Arachnorchis.
In following through a dichotomous key Arachnorchis is immediately separated out from the rest of the Caladenia by the presence of two yellow waxy glands at the base of the column. As this is not the immediate feature seen, the following chart comparing it with the very similar looking Joneseopsis should assist with recognising some of the main distinguishing features.
| SPIDER ORCHIDS (ARACHNORCHIS) |
WISPY SPIDER OR DADDY LONG LEGS (JONESIOPSIS) |
|
| Leaf | Sparse to densely hairy Narrow to broad lanceolate Red base |
Sparsely hairy Slender Red base |
| Stem | Wiry densely hairy | Hairy wiry |
| Flower | ||
| Dorsal sepal | Erect | Erect |
| Tepals
(Petals & Sepals) |
Long & slender with long slender glandular tails or thickened short to long clubs*
Petals and sepals similar size |
Narrow, end in very long thin threadlike glandular tails* |
| Labellum | Trilobed obliquely erect lateral lobes Midlobe often differently coloured to the base |
Small indistinctly lobed
Narrow |
| Hinged | Hinged | |
| Apex | Rolled under at the apex | Rolls under* |
| Margins | Fringed with short to long teeth* | Short, blunt teeth to smooth |
| Calli | Vary from short rounded crowded to long curved and widely spaced | Short blunt congested lamina calli* |
| 2 or more rows | 2 rows* | |
| Basal Gland | 2 yellow at base of the column | None |
| Growth Habit | Loose groups* | Clumping |
*Exceptions in all these descriptions
Labelled Features of a Spider Orchid
Reference
Backhouse, G, (2018) Spider Orchids: The Genus Caladenia and Its Relatives in Australia ISBN: 978-0-9946489 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
Oligochaetochilus excelsus, an impressive name for the winning photo, taken by John Fennell. It was originally formally described and named Pterostylis excelsa by Mark Clement in 1986 from a specimen cultivated from a tuber taken from Eyre Peninsula. This was subsequently published in the fourth edition of Black’s Flora of South Australia. In the early 2000s, the genus Pterostylis was split into several different genera of which Oligochaetochilus was one.
Although not everyone accepted this change, it is helpful for understanding the characteristics of this group. They are found only in Australia and are primarily a semi-arid inland group, sometimes the only orchids to occur in a locality.
Bob Bates has documented some of the drought tolerant and drought avoidance features found in this group as follows.
Drought tolerance:
Drought avoidance:
References:
https://en.wikipedia.org/wiki/Pterostylis accessed 10 May 2018
Jessop, J. P. and Toelken, H. R. (eds) (1986). Flora of South Australia. 4th ed. Adelaide: Government Printers Adelaide.
Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version. NOSSA
Four very different species were entered this month. Ricky Egel’s autumn flowering Coryunastylis fuscoviridis (see February Journal for name usage), Rosalie Lawrence’s winter flowering Diplodium bryophilum and John Fennell’s spring flowering Stegostyla cucullata and Arachnorchis formosa.
It was no surprise that John’s A. formosa (syn. Caladenia formosa) was the winning photograph. Words such as stunning, spectacular, wonderful and attractive are used in the description of this rare orchid and is reflected in its common names – Scarlet Spider Orchid, Elegant Red Spider Orchid, Elegant Spider Orchid and Blood-red Spider Orchid. It is truly a stunning red flower with its drooping petals and sepals (tepals).
A. formosa is part of the large patersonii alliance which is characterised by white to reddish flowers with (mainly) drooping tepals ending in long, slender (sometimes thickened) sparsely to densely glandular (hairy) tails, labellum with short to long marginal teeth. The features that separate A. formosa from others in the complex are the large (~60 mm across) deep red flowers with long (~80mm) tapering, drooping tepals. Similar species to A. formosa is the smaller once common but now extremely rare Caladenia ‘Fleurieu Peninsula’ In Victoria there are some other similar species.
A. formosa is confined mainly to the South East and into south western Victoria.
References:
Backhouse, G., (2011). Spider-orchids – the Genus Caladenia and its Relatives in Australia, Melbourne, Electronic version.
Backhouse, G., et al, (2016). Bush Gems: A Guide to the Wild Orchids of Victoria, Australia, Electronic version.
Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version. NOSSA
A small but varied number of entries for our first competition of the year. Andrew Primer entered a lovely picture Thelymitra azurea from Eyre Peninsula; Thelma Bridle entered Calochilus cupreus one of South Australia’s endangered orchids; John Fennell’s close up of Caladenia prolata and Rob Pauley’s mass flowering of Caladenia carnea.
The winner was Rob Pauley’s C. carnea a wide spread orchid which ranges from across the Eyre Peninsula through to the South East as well as occurring in the Eastern States and Tasmania. Although considered common both nationally and at a state level, there are regions within its range where it is considered to be Near Threatened, Rare and even Vulnerable. Also, despite being common, the Seedbank notes that there are areas of probable decline: Fleurieu (KAN02), Mt Lofty Ranges (FLB01), Eyre Mallee (EYB05), Wimmera (MDD05) and Southern Yorke (EYB01). It is a reminder that not only the rarest species but also that common species can be in decline.
The situation is complicated by taxonomic issues; C. carnea is not only a highly variable species but also a complex of several similar species plus many undescribed species which continues to challenge botanists.
References:
http://saseedbank.com.au/species_information.php?rid=815 accessed 8 March 2018
Backhouse, G., et al, (2016) Bush Gems: A Guide to the Wild Orchids of Victoria, Australia, Electronic version.
Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version. NOSSA
Short Paper 3 Identity of Pterostylis valida (Orchidaceae) by Rudie Kuiter was published in June 2017. In this paper, Rudie has tackled the difficult group of Rustyhoods or Oliogochaetochilus (specifically Pterostylis valida) within the genus Pterostylis. Many of the different species occur in isolated pockets over a wide geographical range. Differences can be subtle but Rudie has sought to clarify the distinction between P. valida and similar species. Click here read the complete paper.
Rudie Kuiter’s Short Paper 2 Taxonomic Status of the Mauve Leek-orchid Prasophyllum suttonii Rogers & Rees, 1912 (Orchidaceae) published in May 2017 documents how he used original source material to determine the identification of a species that was considered extinct. Prasophyllum suttonii belongs to the Prasophyllum odoratum/diversiflorum complex and is very similar to the later named Prasophyllum alpestre. It was considered to be extinct but Rudie’s view was not that it was extinct but that it had been “lost in taxonomy, and its status need to be restored”. His article documents how he used original material to help determine identification of the species he had photographed.
In his summary Rudie has some good advice about how to effectively use the material available –
Click here to read the complete article
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.
Reference
https://en.wikipedia.org/wiki/Nematoceras_dienemum accessed 23 December 2017
http://www.antarctica.gov.au/living-and-working/stations/macquarie-island/location/climate-weather-tides accessed 23 December 2017
http://www.antarctica.gov.au/news/2017/sub-antarctic-orchid-shows-true-colours-far-from-home accessed 23 December 2017
This month’s theme of “more than six flowers” was interpreted in one of two ways. There were six entries that had six or more plants and the other six entries had six or more flowers, predominately the flowers being on one inflorescence.
The competition was tight with Jane Higgs’ Caladenia tentaculata (syn. Arachnorchis tentaculata) winning by one vote. In South Australia it is known as the King Spider Orchid or Large Green Combed Spider and in Victoria is named the Eastern Mantis Orchid. As it is the largest of the Green Combed Spider Orchids, it is easily identified by its size. But there is variation and sometimes there are patches of small sized plants.
This happened to Rudie Kuiter on one of his orchid forays when he came across of patch of C. parva and small sized C. tentaculata growing together. In his book Orchid Pollinators of Victoria (page 29), he records how he distinguished the differences between the two species – “Except for some minor differences in the labellum they looked much the same. In C. tentaculata the upper margin teeth are longest, whilst in C. parva the central ones are longest. Labellum calli usually run into the red tip on C. parva and just short of the red in C. tentaculata, ...”
Though I could not find these details recorded in any of the field guides I consulted, the differences were obvious when comparing the images of C. parva and C. tentaculata on the Retired Aussies website, www.retiredaussies.com
References:
Kuiter, R. H., Orchid Pollinators of Victoria, Fourth Edition. Aquatic Photographics
NOSSA 