Advice from the past – Start Watering

In 1984, G.J.Nieuwenhoven was the editor of the NOSSA Journal.  In February of that year he wrote the following:

Welcome back to NOSSA.

 After the holiday break we are all looking forward to the next meeting to talk about our favourite plants and renew friendships.

Several members have reported an early start to the terrestrial season with Pterostylis species, a couple of Diuris species popping up already.  For some of the eastern states Pterostylis of the cauline group this is normal, especially if you keep the pots cool during the summer (a cellar is ideal but underneath a shaded bench in the shadehouse will do nicely). Very light watering should take place when the first shoots appear but do not overdo the watering or place pots in the sun for we are sure to get some more hot weather yet and this could cook your plants before you know it.

The Diuris are really out of season but it was probably the rain in late December and early January that started them off, anyway, these too should be kept slightly damp if they are up.

If you have not finished repotting by now it would be best to leave it until next year as the new shoots which are already beginning to grow from the tubers are very easily broken off while sifting them from the soil.

Apart from that all you can do is wait for the rains to come in March and then start searching for plants to appear – and keep those fingers out of the pots or you may damage one of your best plants looking for the new growths.

This is also the time to start taking notes when plants first appear, etc.:

  • when they flower and how many flowers from a given number of tubers;
  • what kind of soil; what conditions (i.e. shaded or not, damp or dry).
  • Anything that may assist in years to come to help you understand and grow our orchids better and, more importantly, multiply them.
  • A card index system would be a good way to store information, otherwise an exercise book will do.

                                                            Editor

The timing of the article tallies with the advice that was recently given at the end of February – start watering the terrestrials now if you haven’t already begun.  Hopefully by the flowering time you will have a lovely display of terrestrials such as the Thelymitra, Arachnorchis and Caladenia featured below.

 

Pot of Thelymitra Kay Nesbitt Cultivar copyPot of Arachnorchis argocallaPot of Caladenia latifolia cultivated by Les Nesbitt

2014 November Photograph Competition Part 2

Part Two of the November competition consisted of photographs of insects on orchids. There was quite a range of insects but the winner was a draw between Cyrtostylis robusta (Winter Gnat Orchid) with an ant and Pterostylis curta (Blunt Greenhood) with a midge fly; both taken by Doug Castle.

With today’s technology it is not only easier to take crisp images but fine details can be seen particularly when enlarging the image. Hence when the pictures are enlarged it is possible to see hairs on the ant and feathered antennae on the midge fly.

With identifying orchids, it is often the detail that is important. Both of these orchids are distinctive and can be readily identified but it is good to examine why this is the case.

Pterostylis curta (Blunt Greenhood)
Pterostylis curta (Blunt Greenhood)

With the greenhood, there is enough detail to see that the dorsal sepal and lateral petals have united to form a galea, ie hood, and that the lateral sepals are semi-fused and erect resulting in lateral orifices (side gap) between the two structures. These are some of the features that separate Pterostylis* from the other greenhoods such as Diplodium, Speculantha and Taurantha. This becomes apparent when browsing through the greenhood photographs, pages 286 to 339, in Jones “A Complete Guide to Native Orchids of Australia”. Having established that the plant is a Pterostylis, the twisted labellum is diagnostic of a P. curta as it is the only one that is described with a twisted labellum. Although not all the identifying features are present, enough information is available in this picture for identification.

In contrast the photograph of the Cyrtostylis robusta only has sufficient data to confidently identify it as a Cyrtostylis species, having a distinctive labellum that is larger than the lateral sepals and petals. In South Australia there are only two species and according to Bates (2011), the distinguishing features between the two

Cyrtostylis robusta (Winter Gnat Orchid)
Cyrtostylis robusta (Winter Gnat Orchid)

appear to be the leaf, the bud and the labellum. In this picture, the angle of the image does not give a clear view of the labellum (it could possibly be damaged) and of course there is no bud or leaf. It is possible that the pale edges of the dorsal sepal may give a clue to species identification as C. reniformis has mainly darker buds than C. robusta. Obviously Doug was able to identify it from his observations of the other features not present in this photograph.

In summary, one image is not always sufficient for identification. As was discussed on the night, to confirm identification, orchids should always be photographed from more than one angle, including pictures of other parts of the plant.

*In South Australia, Pterostylis foliata is a possible exception as it has no obvious lateral orifice.

References

Jones, D.L., T. Hopley, S.M. Duffy, K.J. Richards, M.A. Clements & X. Zhang (2006) Australian orchid genera. An information and identification system. CSIRO Publishing: Collingwood, Vic.

Bates, R.J. (2011) South Australia’s Native Orchids. DVD-ROM. Native Orchid Society of South Australia Inc.: Adelaide.

Jones, D.L. (2006) A complete guide to native orchids of Australia, including the island territories. New Holland Publishers: Sydney.

Another Summer Orchid

Just on Christmas, NOSSA received an enquiry from Tim in the South East about an orchid he had photographed.  He knew about Dipodium roseum but in 20 years he had not seen one like this one.

From the photograph that he’d sent, it was obvious that it was a Gastrodia.  In South Australia there are three species ranging in size from the smaller G. vescula (Limp Potato Orchid) through to G. sesamoides (Cinnamon Bells or Common Potato Orchid) to the larger G. procera (Tall Potato Orchid).  Whilst G. vescula and G. procera are limited in South Australia to the South East, G. sesamoides is also found in the Southern Lofty and Kangaroo Island regions.

Tim’s orchid was G. procera.  The features that set it apart from the other two were the time of year – late December whereas both G. sesamoides and G. procera would have finished flowering (and for 2014 most orchids finished flowering earlier than usual); the spike was crowded and the plant was upright but G. sesamoides has a bent or droopy spike when in bud and G. vescula is small with very few flowers.

Though Tim considered the photographs to not be very good, he’d photographed the necessary features to help with identification. Another feature seen in his picture is the warty appearance of the plant compared with the photograph of the G. sesamoides.

Gastrodia procera or Tall Potato Orchid
Gastrodia procera (Tall Potato Orchid) Note the upright spike and the ‘wartiness’
Gastrodia sesamoides (Cinnamon Bells or Common Potato Orchid)
Gastrodia sesamoides (Cinnamon Bells or Common Potato Orchid)

 

 

 

 

 

 

 

 

 

 

Although it is has no conservation rating federally and may even be considered secure in the Eastern States, in South Australia it is rated endangered, so well done to Tim for spotting it!

 It was possible to identify this orchid from the information found in South Australia’s Native Orchids, an electronic book produced and sold by the Native Orchid Society of South Australia.  Identification was confirmed by one of our most knowledgeable members.

2014 November Photograph Competition Part 1

11 sm CD Arachnorchis sp with hover fly

With a theme of Orchids and Insects for the November meeting it was hoped that there would be some entries with pollinators and therefore there would be two categories Insect Visitors and Pollinators. This month’s article will feature the Pollinator section and Insect Visitors in the next month.

In all there were four potential pollinator photographs. The insects were either scrounging around at the base of the column or else they had the pollinia attached to them. Unfortunately only one was a true pollinator so the category became Insects with Pollinia. The winning photograph of Arachnorchis brumalis with an unidentified hoverfly was taken by Chris Davey. Interestingly the other two pictures also featured Arachnorchis species with the hover fly Simosyrphus grandicornis. Resembling a wasp but minus the sting, this species is one of the common hover flies native to Australia.

Called Hover Flies owing to their ability to hover motionless in one spot, they are also known as Flower Flies because they are often found hovering around as well as pollinating flowers. It is not surprising, therefore, to find them around orchids. Yet instead of being called pollinators they are non-pollinators (Bates & Weber 1990). They visit the orchids, forage inside the flower and may even manage to collect some pollinia but that is all. They may not necessarily visit another flower of the same species but if they do, they will fail to deliver the pollinia to the stigma2.

Rudie Kuiter agrees with Bates that hover flies are not orchid pollinators but just when we think we have worked it out he adds “but we have at least one orchid in Victoria that is pollinated by hoverflies and witnessed now several times and this is Caladenia catenata” (synonym Petalochilus catenatus). Notwithstanding the case for this species, it would appear that in most cases hoverflies remove pollinia so that it is not available to a more specific pollinator.

Why then are the hover flies attracted to the orchids? Is it for food? An internet image search revealed that hover flies visit the flowers of many different genera including Thelymitra and Diuris. This is interesting because flowers are the food source for hover flies but though many orchids promise food, many species do not produce the nectar and pollen (as a food source) that they desire. Diuris and Thelymitra belong to this group of non-nectar producing flower. Other orchids that don’t produce nectar include Gastrodia, Dipodium and the Duck orchids. Again, there are orchids such as Crytostylis which produce minimal nectar and with Prasophyllum the nectar is hidden in cells that require puncturing – not a good food source!

Having discussed hover flies as non-pollinators, in this month’s competition, which photograph had a pollinator? – It came last and was Robert Lawrence’s photograph of a native bee on a Dipodium pardalinum, another non-nectar producing orchid. The story of this photograph was featured in Photographing Orchid Pollinators, April 2014 Journal as well as in a previous blog on Photographing Pollinators.

References:

Smith James, Information Centre, South Australian Museum, personal communications

Kuiter Rudie personal communications

Bates and Weber, Orchids of South Australia, 1990

Australian Museum, http://australianmuseum.net.au/Hover-flies Accessed 4th December 2014

Brown, et al, Field Guide to the Orchids of Western Australia, 2013

Jones, Native Orchids of Australia Including the Island Territories, 2006

Bates, South Australia’s Native Orchids 2011 DVD-ROM

Martin, The Vocabulary of Orchids: An Amateur’s Perspective, 2005

1Pollinia is basically a coherent compact mass of pollen that allows the pollen to be transported as a single unit

2The stigma is a sticky depression (or swelling) at the front of the column, the receiving surface for the pollinia that is necessary for germination.

Orchid Season

South Australia has some very interesting and unique orchids but it is not always possible see them  either because one cannot get out to see them or the season has been poor with inadequate rain at the right time.  So, one of NOSSA’s member has produced a video.  It starts in autumn and goes through to summer.

So sit back and enjoy ……

2014 September Winning Photograph

The winning picture was a single flower of Thelymitra epipactoides (Metallic Sun Orchid) taken by Rosalie Lawrence. This picture was cropped from a photograph taken on a mobile phone. Phones have come a long way since the days of Alexander Graham Bell!

Thelymitral epipactoides or Metallic Sun Orchid

T. epipactoides is a special orchid both in its beautiful colourings and that it is one of our rarest orchids. This endangered species has been well studied in an effort to prevent its demise with the result that there is an abundance of information about it. Recently, with the knowledge gained, Dr Nouska Reiter of the Australian Network for Plant Conservation (ANPC) and her team have managed to cultivate 3,000 plants with the plan to re-introduce them back into the bush in the Wimmera area.

Following are some interesting points from two good sources, which are the

  1. Biodiversity Information Resources Data page  (quotes in blue)
  2. Species Profile and Threats Database page  (quotes in brown)

 

Life Cycle

  • (2)……can remain dormant as a tuber in the soil for up to nine years ……….

(But once a plant has flowered)

  • (2)…….Plants can produce flowers from their second year of growth onwards for up to four consecutive years, but no more. Individual plants can remain dormant for up to two years then grow to produce flowers, but if dormant for four years or more, plants generally do not reappear. …..
  • (2)…… Detailed monitoring suggests that mature plants only live for about 10 years before dying (Cropper 1993). ……..
  • (2)……..flowers open when the relative humidity is lower than 52%, air temperature is above 15 °C, and there are clear skies ………….
  • (2)……..Flowers remain for up to four weeks but wither a week after pollination ……
  • (2)……. fungus is required to initiate successful seed germination (Calder et al. 1989) and seeds cannot survive more than two weeks without associating with the fungus ………

Plant Information

  • (1)…….Flower colour is highly variable, brown, copper, blue and green being the main colour groups which are determined by the proportion of red, blue and green epidermal cells, some of which are reflective giving a metallic appearance. …….
  • (2)….The leaf is loosely sheathing ………
  • (2)…Mature non-flowering plants have slightly narrower leaves to 51 cm long and not sheathing …
  • (1)………Flower colour is highly variable, brown, copper, blue and green being the main colour groups which are determined by the proportion of red, blue and green epidermal cells, some of which are reflective giving a metallic appearance. ………

Topography:

  • (2)…. is undulating plains, crests of hills, gentle slopes of low broad ridges and at the bottom of broad, shallow swales (Obst 2005). It grows in sandy soils over a clay subsoil, with these soils having a tendency to become waterlogged in winter and spring, and drying out in summer and autumn ……
  • (2)…..This species is a post-disturbance coloniser, utilising early successional stages after disturbance events such as human activities, fire, animal activities such as scratching of the soil, or associated vegetation disturbance. ……
  • (2)……..requires open sites for flowering and seedling recruitment (Calder et al. 1989). ………

Population Size

  • (1)……Population estimates vary from about 1050 plants in Australia (DEH 2006), to less than 3,000 plants (Coats et al 2002). More recent assessments suggest the population could be less than 1500 plants in the wild …….
  • (2)……In the Murray Darling Basin and South East Regions of South Australia there were ten populations of the Metallic Sun-orchid recorded in 2004 by Obst ……..

 

Reminder – November theme is Orchids and Insects (Spiders and other such critters are honorary insects)

Bananas Trigger Flowering of Orchids

 

Some native terrestrial orchids only flower in the season after a bushfire.  They are stimulated by the hot gases given off during the fire.  One of those gases is ethylene.  Bananas are shipped down from Queensland to the southern states of Australia as green bananas to stop fruit fly outbreaks.  On arrival they are put in sealed rooms and exposed to ethylene gas.  The bananas ripen a few days later.  Traces of ethylene remain in the banana skin.  Overripe fruit also emits ethylene gas.  Orchid flowers do not last long if ethylene is present in a closed glasshouse.

We know that dormant tubers exposed to ethylene often flower the next season.  The best example is the Hare orchid Leptoceras menziesii.  In summer I put dormant tubers in a small dish in a plastic bag with a banana skin and seal the bag with a rubber band.  The skin may go mouldy so should not touch the tubers.  I leave the bag inside my shed for about 2 weeks then remove the tubers and pot them up.  The exposed plants make leaves almost twice as large as normal tuber leaves.  This procedure should not be carried out with the same plants the following year as they may get exhausted and die out.  I have found results with other shy flowering species are not so reliable.  Maybe they need a stronger does of ethylene.

Article by Les Nesbit

Banana & Banana PeelVol 38 No 5 June 2014

NOSSA Journal

Australian Orchids & the Doctors they Commemorate Part 8 of 20

Edwin Daintrey (1814-1887)

A medical student who abandoned his medical career just before graduation; he emigrated to Sydney, where he practised as a solicitor, cofounded the Linnean Society of New South Wales, and was appointed honorary secretary of the Australian Library in Bent Street.

Orchid species: Pterostylis daintreana

Australian Orchids and the Doctors they Commemorate Part 5 of 20

Having looked at the background, Professor Pearn documents the individual doctors and orchids.  In the original paper the doctors were listed alphabetically but these posts will be in chronological order based upon the doctor’s year of birth.

Daniel Solander (1733 – 1782)

A medical student in Sweden and London, and botanist-librarian on the Endeavour voyage to Austalia (1769 – 1771); his name is commemorated in the names of Australian species of Aciacia, Banksia and Geraniums.

Orchid species: Orthoceras strictum (= Orthoceras solandri)

The type specimen is from New Zealand.

 

June 2014 Winning Photograph

 

06 DM A leptochila sm
Arachnorchis leptochila spp. leptochila (syn. Caladenia leptochila)

There were many more entries than usual this month but the winner was a photograph by David Mangelsdorf.

Looking back over the last three winners, a royal theme emerges.  In April it was the elegant Queen Orchid, in May the flamboyant Queen of Sheba and this month it is the dignified Queen Spider Orchid (a statelier name than the more usual common name of Narrow Lipped Spider Orchid).

The botanical name for this species is Arachnorchis leptochila spp letptochila (syn. Caladenia leptochila).  An endemic species of South Australia, it is mainly found in the Mount Lofty Ranges where it favours leached stony soils.  Flowering in spring, it is easily recognised by the upswept segments and narrow labellum.

Usually these orchids are characterised by dark clubs which can be seen even in bud, but in this picture they are light coloured.  This could be due to variation with the species, as occasionally pale coloured flowers have been found.  Interestingly in doing an image search on the web I found none with light coloured clubs.