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.
|WISPY SPIDER OR DADDY LONG LEGS
|Leaf||Sparse to densely hairy
Narrow to broad lanceolate
|Stem||Wiry densely hairy||Hairy wiry|
(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*|
obliquely erect lateral lobes
Midlobe often differently coloured to the base
|Small indistinctly lobed
|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
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
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.
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
Orchids are unique in the floral world. Two distinctive characteristics that set orchids apart from other plants are the labellum and the column.
The labellum is a modified petal. It is extremely varied in appearance; “often lobed, spurred, adorned with glands, appendages of calli (callus, a hardened swelling or thickening of the skin), sometimes mobile and highly irritable and often brightly coloured”. * The labellum is important for pollination.
The column (as described by Bates and Weber) “is a distinctive feature of all orchids and a unique structure in the plant kingdom. It is formed by fusion of the male parts ‘stamens’ and female organ ‘pistil’.”*
Below are examples of the various types of labellums and columns in some South Australian terrestrial orchids. Each genus has its own characteristic labellum and column.
*Bates and Weber Orchids of South Australia 1990
This month’s theme for the photo competition was blue and white. White flowers can occur as a result of lack of colour such as Rosalie Lawrence’s Caladenia latifolia (Pink Fairies) which is normally pink. White orchids can also occur naturally such as the Arachnorchis argocalla (White Beauty Spider Orchid) and Arachnorchis intuta (Ghost Spider Orchid) both photographed by John Fennel, or as a dominant colour such as Lorraine Badger’s Eriochilus collinius (syn Eriochilus sp Hills Woodland).
Of the blue orchids, both Ricky Egel and John Badger entered pictures of Thelymitra x truncata (Blue Spotted Hybrid Sun Orchid) whilst Robert Lawrence entered a Thelymitra grandiflora (Giant Sun Orchid) which was the outstanding winning picture.
Blue in the floral world is unusual colour in the floral world for it is not a naturally occurring colour. In fact, “[t}he key ingredient for making blue flowers are the red anthocyanin pigments. Less than 10 percent of the 280,000 species of flowering plants produce blue flowers.” (Lee, 2010 as cited in Oder 2014).
Whilst blue orchids occur outside of Australia, their “colour cannot rival” … “the intensely blue flowers” … “especially [are] unique in the orchid world” … “of their Australian counterparts. The sun orchids (Thelymitra) in particular are famous for their sky blue flowers.” (Ronse 2008: 103)
Based upon Jones 2006 tome, the following genera have true blue orchid species – Cyanicula (9 species), Pheladenia (1 species), Epiblema (1 species) and the largest group Thelymitra (about 65 out of potentially 118 species) plus one hybrid, XGlossodenia tutelata. Of the epiphytes, blue is almost non-existent except for three which Jones lists that rarely might be bluish and they are Vappodes bigibba, V. lithocola and V. phalaenopsis*.
With such rarity, is it any wonder then that the Chinese attached special significance to it as a plant that could cure lung disease and the Aztecs saw it as a symbol of strength.
*Names used as they appear in Jones 2006 tome
Jones, D. L., A Complete Guide to Native Orchids of Australia Including the Island Territories. Reed New Holland
Lee, David (2010), Nature’s Palette: The Science of Plant Color< Chicago, University of Chicago Press
Oder, T, The Science of Blue Flowers https://www.mnn.com/your-home/organic-farming-gardening/stories/the-science-of-blue-flowers accessed 6 July 2017
Pretty Zesty All About Blue Orchids http://www.prettyzesty.com/2012/11/all-about-blue-orchids.html accessed 6 July 2017
Leo Davis always has some interesting insights from his orchid observations. In this article he examines the position of the tepals (petals and sepals) in particular the Moose Orchid which he saw for the first time this year.
Have a close look, next season (winter to early summer) at some of our native lilies. Start with the jolly bulbine lily (Bulbine bulbosa), no longer a true lily incidentally, because it now resides in family Aspodelaceae, along with the grass trees. You will find three yellow petals at 12, 4 and 8 o’clock and closely behind them three almost identical sepals at 2, 6 and 10 o’clock, so at first sight you see six apparently identical tepals (sepals and petals). Move on to the rush fringe-lily (Thysanotus juncifolius), as described in Ann Prescott’s ‘It’s Blue With Five Petals’. Clive Chesson is more up to date and tells me it is now T. racemoides. Again it is no longer a true lily, now sitting in family Asparagaceae. Here the tepals are noticeably different. Three wide densely fringe edged petals will be found, if you view the flower face on, at 12, 4 and 8 o’clock. The narrow non fringed sepals sit close behind at 2, 6 and 10 o’clock. These are just a generalisations because if the flower turns only about 60o a sepal will be at the top.
Most orchids, while close relatives of the true lilies and the one time lilies, do not show these arrangements. Let’s start with some that do.
In the large duck orchid (Caleana major) the petal at 12 o’clock, the dorsal petal, is modified, as in most, but as usual, not all, orchids, to become a labellum. In this charmer the labellum takes the form of a duck’s head. Its function is to snap down trapping a pollinator insect in the cup shape column below it, forcing it into contact with the sticky off white stigma and/or the yellow pollinia below it. Look closely and you will find the other two narrow petals drooping at around 4 and 8 o’clock. Two folded, twisted sepals can be clearly seen at around 1 and 11 o’clock. The third sepal, at 6 o’clock, is tucked in behind the cup shaped column. Note that, as with lilies, the top tepal is a petal.
The leek orchids (genus Prasophyllum) follow this pattern and also have their labellum at around 12 o’clock. These orchid groups, which are up the right way, are said to be ‘not upside down’, using the technical term ‘non resupinate’.
Most orchids are ‘upside down’ and are called resupinate. The whole flower rotates 180o, clockwise or anti I don’t know, at the embryonic stage. But let’s start with somewhat of an exception with the sun orchids (genus Thelymitra) which do not have a petal modified as a labellum. But they are indeed upside down.
Have a close look at the Thelymitra benthamiana flower. Note that the three petals, at roughly 2, 6 and 10 o’clock, are in front of the three slightly larger but very similar sepals, at 12, 4 and 8 o’clock.
Note that the top tepal is a sepal. The flower is upside down, that is resupinate. In most orchids the petal at 6 o’clock would be modified to be a labellum.
The Arachnorchis (possibly Caladenia to you) stricta, from Sherlock, out in the mallee, is more typical of terrestrial orchids in SA. It is upside down, that is resupinate, and has a petal modified to be a labellum.
The bottom petal has become a wide labellum, with fine edge combs and parallel rows of rich plum coloured calli covering its centre. Out at roughly 3 o’clock is a narrow petal, the other invisible on the other side. At the top, pressed tightly against the column, a sepal arches forward. Two larger sepals extend down at around 5 and 7 o’clock.
When I saw my first, my only, moose orchid, this season, I was in such a state of excitement that it looked to me to be up the right way, that is to say upside down.
Have a look. Two narrow short roughly vertical petals at about 1 and 11 o’clock. There are two sepals at just past 3 and just before 9 o’clock. That’s OK but where is the other sepal? Are there it is, where it should be, at midday. But hang on, it’s behind the flower stem (peduncle) and where is the column?
Holding the labellum up with a stick I found the column, the stigma and the pollinia, underneath the labellum. The third sepal now appears to be at 6 o’clock. And it all became clear. This flower was up the right way (non resupinate) but it has turned forward, on its peduncle, by about 180o, to become upside down, but not in the manner of resupinate flowers, because it is back to front. It is an inverted non resupinate flower. Still with me?
For the final meeting of the year we chose the best of the 2016 monthly winners of the picture competition.
Here in Australia we are fortunate to have such a variety of orchids. They may not be as big and showy as some of the overseas orchids but the diversity of shapes fires the imagination as reflected in this year’s monthly winners, when put together. The common names of the winners – spider, leopard, flying duck, cowslip, zebra, helmet, bluebeard and greenhood – reinforce this theme of diversity.
Patterns and colours contribute to the variety of our orchids. Australian orchid colours run the gamut of the rainbow and more, with Australia being home to most of the naturally occurring blue orchids in the world. This colour fascinates and allures people around the world so much so that nurseries will dye a white orchid blue because it will sell. There is even a website devoted to the colour called, not surprisingly, Blue Orchid and the popular band master Glenn Miller wrote a song titled Blue Orchids (1944).
Could this be why the very clear winner for the year was Claire Chesson’s Pheladenia deformis common name Bluebeard or Blue Fairy?
Claire Chesson on your most beautiful picture.
Claire won the August competition.
As a reminder, below are the other winners for the year. Click on the image to see the related articles.
February 2016 Photographer: Pauline Meyers
March 2016 Photographer: Judy Sara
April 2016 Photographer: Claire Chesson
May 2016 Photographer: Pauline Meyers
2016 June Photographer: Ros Miller
2016 July Photographer: Robert Lawrence
2016 September Photographer: Bevin Scholz
2016 October Photographer: Helen Lawrence
Quite a few pictures were entered this month.
Ricky Egel’s Thelymitra x irregularis,
Pauline Myer’s Caladenia falcata and Caladenia carinsiana;
Margaret Lee’s Diuris orientis and Nemacianthus caudatus;
Judy Sara’s Arachnorchis tensa;
Greg Sara’s Arachnorchis stricta which had an unusual green coloured flower;
and Helen Lawrence’s Arachnorchis argocalla.
Helen’s picture of the nationally endangered A. argocalla was the outstanding winner. Now known as the White Beauty Spider Orchid^, it was featured last year as a winner with Pauline Meyer’s June 2015 entry*.
This is one of our largest spider orchids. For size, beauty and delicacy it rivals the Western Australian Caladenia longicauda ssp. eminens (White Stark Spider Orchid) and A. venusta, syn. Caladenia venusta (Graceful Spider Orchid) from Victoria and the South East.
It shares many similarities with these two species in that they are reasonably good size white flowers with a stiffly hinged labellum that has long, thin teeth and the segments have threadlike tips without clubs. It is separated both geographically and in the type of habitat from these two species. A. argocalla is a plant of the inland hills and valleys.
Though primarily a white flower and part of the A. patersonii complex, A. argocalla has red colouring in the labellum which according to Backhouse may possibly indicate genetic introgression (that is long term mixing of the gene pool) with either the A. reticulata or A. leptochila complexes. Certainly, the colour of the labellum was quite variable ranging from white through to a deep red.
^Previously known as Common White Spider Orchid because of its abundance but now only known to a limited number of locations.
*NOSSA Journal, July 2015
Department of the Environment (2016). Caladenia argocalla in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 3 Nov 2016 16:31:39 +1100
Introgression https://en.wikipedia.org/wiki/Introgression Accessed 4 November 2016
Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA
Jones, David L (2006) A complete Guide to Native Orchids of Australia, Frenchs Forest, NSW: Reed New Holland
Backhouse, G (2011) Spider-orchids the Genus Caladenia and its Relatives in Australia
NB: November Competition will be judging the monthly winners from this year.
The following video is by Orchid Hunter, Julian Pitcher. Julian is concerned about the conservation of orchids and is also keen to teach others about Australia’s unique orchids. At the time of the visit, Julian was resident in Victoria; now he resides in Queensland. Enjoy an interstate visitor’s view of our beautiful orchids.
This is the last of the three terrestrial fact sheets in Culture Notes that NOSSA has produced on growing terrestrial orchids. All three facts sheets can be downloaded – Click on the following for Fungi Dependent, Slow Multipliers and Fast Multipliers.
FLAGBEARER SPECIES: Caladenia tentaculata (synonym Arachnorchis tentaculata)
Some 3/4 of Southern Australian terrestrial orchids are fungus dependent throughout their life cycle. Orchids that are fungus dependent have very specific cultural requirements. The fungus must be grown in the pot with the orchid. Sometimes a third entity such as a shrub or tree is involved in the fungal relationship.
A minimum disturbance culture is used.
Limited numbers are available each year. Other fungus dependent species are rarely available. Those in cultivation have mostly come from rescue digs in the past. NOSSA has started a seed kit project to help overcome this vacuum.
GROWTH HABIT: Australian ground orchids follow an annual growth cycle comprising 6 – 8 months as growing plants under cool (5 – 20°C max, 0 – 14°C min) moist conditions and 4 – 6 months as dormant tubers in hot dry (18 – 42°C max, 12 – 30°C min) conditions. The new tuber is produced in winter – spring. Each tuber sends up a shoot to the surface in Autumn and leaves grow rapidly in late Autumn/early Winter as temperatures fall and the rains set in. Sometime in October/November the leaves go yellow and then brown and dry as the days get longer, hotter and drier in late Spring.
LIGHT/SHADE: In Adelaide they thrive in a shadehouse of 50% shadecloth. Some species prefer heavy shade, others full sunlight, but most will adapt to a wide range of light intensity.
If the leaves and stems are weak and limp or if the leaf rosettes are drawn up to the light then the shading is too dense and the amount of light should be increased. FDs are mostly spring flowering and like higher light intensities at flowering time. flowers may have pale colours if placed in heavy shade, even temporarily, when buds are just starting to open.
In very cold areas an unheated glasshouse may be required for frost protection although light frosts do not worry the majority of species.
AIR MOVEMENT/HUMIDITY: All species like good air movement and will not thrive in a stuffy humid atmosphere especially if temperatures are high.
POLLINATION/SEED COLLECTION: FDs seldom multiply so must be propagated from seed.
Flowers on the strongest plants of the same species growing in pots are cross pollenated by hand to set seed pods. The flowers collapse in a day of so and pods ripen in 4-8 weeks. Pods are collected as they change colour from green to brown, which happens quickly on a hot day in October/November. Tea bags can be tied over the pods to catch the dust like seed if frequent visits to site are not possible.
Pods are stored dry in paper envelopes indoors over summer. Seed can be sprinkled on mother pots or scattered on bush sites.
SEEDLING CARE: Seedlings can be raised by sowing seed around potted mother plants.
At Easter time, just before the rainy season begins, the dust-like seed is mixed with fine sand in a pepper shaker (minimizes seed loss) and sprinkled on top of the pots and watered in. Germination occurs in Autumn/Winter as that is when the fungi are most active. Tiny leaves appear from July to October. The seedlings form miniscule tubers on droppers about 1 – 2cm below the surface. Seedlings take up to five years to reach flowering and are best left undisturbed until larger.
WATERING: The soil should be kept moist at all times during active growth by watering gently if there is no rain. Hand watering is especially necessary in spring as soil in pots dries out more rapidly than in the garden. Watering must be done slowly so that the mat of needles on the surface of the pot is not disturbed. Slugs and snails love these plants and must be kept under control. Raising the pots off the ground on galvanised steel benching is very effective in controlling these pests.
After the leaves have turned yellow, let the pot dry out completely to dry up the old roots and tubers otherwise they may turn into a soggy mouldy mess and rot may destroy the adjacent new tubers.
REPOTTING: The plants are not repotted but left in the same pot year after year.
SUMMER CARE: Keep the pots shaded and allow the pots to dry out between light waterings until mid-February when they should be set out in their growing positions and watered a little more often. The tubers of some species will rot if kept wet during the dormant period, others will produce plants prematurely which are then attacked by pests such as thrip and red spider and fungal diseases in the warm weather.
A thin layer of new leaf litter is placed on top of the existing leaf litter each summer to feed the fungus. Chopped gum leaves or sheoak needles are suitable.
FERTILIZING: NO FERTILISER
OTHER CULTURE NOTES: