November 2015 Winning Photograph

November’s theme was hybrids. Orchids, more than any other plant family, are likely to produce natural hybrids. Even though the overall occurrence of natural hybridisation in orchids is low, it occurs often enough to make some species identification challenging.

Hybrids mainly occur between species of the same genera such as Jenny Pauley’s Arachnorchis brumalis x A. conferta

11sm JP Arachnorchis brumalis x conferta
Arachnorchis brumalis x A. conferta

but, less commonly, it can occur between genera as seen with Pauline Meyer’s Caladenia latifolia x A. brumalis

11 sm PM C latifolia X A brumalis
Caladenia latifolia x Arachnorchis brumalis

and her Western Australian photograph of Caladenia x enigma; a hybrid between C. falcata and Drakonorchis barbarossa.

11sm PM Caladenia x enigma
Caladenia x enigma


Jones (2006) states that “Natural hybrids are more common in some genera, such as Arachnorchis, Caladenia and Diuris, than in others.” To this list could be added Thelymitra as seen with both of the winning pictures T. x truncata and T. x irregularis. Interestingly with these two hybrids, the parents are not always the same; the parents for T. irregularis could be T. ixiodies or T. juncifolia with either T. carnea or T. rubra.

11 sm RAL Thelymitra x irregularis.jpg
Thelymitra
x irregularis

A similar situation occurs with T. truncata with the parents consisting of T. juncifolia and any member of the T. pauciflora (including T. albiflora, T. arenaria, T. bracteata, T. brevifolia, T. cyanapicata, T. pauciflora) or of the T. nuda complex.

11 sm RWL Thelymitra x truncata
Thelymitra
x truncata

The conditions necessary for hybridisation are that the parents must grow in the same area, have overlapping flowering time and share the pollinator. Brown et al (2103) make the additional observation – Hybrids are more common between wasp and bee-pollinated species than between two wasp-pollinated species or two bee-pollinated species.   … However, rare hybrids between species using the same pollination strategies, do occasionally occur …

Obviously hybridisation is more likely to occur when there is an abundance of the parent species. This situation can occur when there is mass flowering following fires or good seasonal rains. Site disturbances either through natural causes or clearing can result in increased incidence of hybridisation.

Hybrids are often infertile and will only last for the life of the individual plant but some have the ability to reproduce vegetatively and, provided the conditions remain favourable, may persist for several years.

One situation that can occur is hybrid swarm. When these occur they can make orchid identification challenging. Hybrids share the characteristic of both parents and by careful observation this can be deduced but swarms introduce an added complexity because the hybrid can backcross with either of the parents or cross fertilise with themselves. The result is a wide range of variation which makes orchid identification difficult.

Finally, some orchids will not hybridise even though the conditions are right. This could be due to specific pollinator or possibly chemical or genetic barriers.

References:

Brown et al (2013) Field Guide to the Orchids of Western Australia, Floreat, WA, Simon Nevill Publications

Jeans, Jeffrey & Backhouse, Gary (2006) Wild Orchids of Victoria, Seaford Vic, Aquatic Photographics

Jones, David (1988) Native Orchids of Australia, Frenchs Forest, NSW, Reed Books

Jones, David (2006) A Complete Guide to Native Orchids of Australia including the Islands and Territories, Frenchs Forest, NSW, Reed New Holland

Introduction to Australian Orchidaceae CD-ROM

https://www.anbg.gov.au/cpbr/cd-keys/orchidkey/html/intro-c_hybrid.html   accessed 7th December 2015

Bates, Robert (2011) South Australia’s Native Orchids NOSSA DVD Adelaide

Spotted Pink Sun Orchid – Beautiful, but Only a Hybrid

https://nossa.org.au/2014/09/26/thelymitra-x-irregularis-beautiful-but-only-a-hybrid/ accessed 7th December 2015

 

 

Clues to Orchid Identification – Columns

Orchids can be incredibly easy to identify or frustratingly difficult.  For instance, the Flying Duck orchid is easily recognizable.  The name says it all. But for many other orchids, particularly the ubiquitous blue sun orchids, it is necessary to make careful observations.

 

 

Which is which
In this collage there are several species, but which is which?

 

For sun orchids the most important distinguishing feature will often be the column, details of which are described or illustrated in orchid keys.  For example Bates and Weber, Orchids of South Australia (1990) has an illustrated dichotomous keys showing the different types of columns.

As part of the key, drawings of the column were included
Images from Bates & Weber, Orchids of South Australia, pages 147 to 150; courtesy of the Board of the Botanic Gardens and State Herbarium.

With today’s cameras, it is possible to photograph the column, preferably from front, side and above.  This helps greatly with identification.

The following photographs illustrate the variety of columns.

Thelymitra alcockiae
Thelymitra alcockiae

 

Thelymitra grandiflora
Thelymitra brevifolia
Thelymitra brevifolia
Thelymitra cyanea
Thelymitra cyanea
Thelymitra peniculata
Thelymitra peniculata
Thelymitra pallidifructus
Thelymitra pallidifructus
Thelymitra juncifolia
Thelymitra juncifolia
Thelymitra inflata
Thelymitra inflata
Thelymitra arenaria
Thelymitra arenaria

 

Thelymitra megcalyptra
Thelymitra megcalyptra
Thelymitra X truncata - a natural hybrid
Thelymitra X truncata – a natural hybrid

And it is not only the blue orchids that can be a problem, in South Australia; there are three pink orchids which are different in size and flowering time, features that are not obvious in a photograph,  so the column is a helpful identification tool.

Thelymitra luteocilium
Thelymitra luteocilium – has tufted hairy column arms
Thelymitra rubra
Thelymitra rubra – has finger-like column arms and no tuft
Thelymitra carnea
Thelymitra carnea – has smooth column arms

 

And just what is the column? It is the reproductive organ of the orchid flower and is unique amongst plants because it is the fusion of the male (stamens) and female (pistil) parts.  It is usually found in the centre of the flower and both releases and receives the pollen sac.

 

 

 

 

 

 

2015 February Winning Photograph

02 CC Thelymitra glaucophylla sm

The number of photographs may have been few but the quality was present. The clear winner was Claire Chesson’s Thelymitra glaucophylla (Glaucous Leaf Sun Orchid). Flowering from October to December, this endemic grassy woodland species of the ranges was only published in 2013 by Jeff Jeanes in the Mulleria 31:3 – 30 (2013) but it had been recognized much earlier by Bob Bates and has appeared with this name in his electronic Orchids of South Australia since 2005. It belongs to the T. nuda complex, of which there are 15 species, six of them having only been published in 2013. This complex is characterised by having large scented blue multiple flowers that open freely.

Not seen in this picture is the leaf and though the leaf is highly variable – 10-50cm long, 8-20mm wide, erect and short, long and flaccid, Jeanes mentions that T. glaucophylla “can be identified with a high degree of confidence from the mature leaves alone” (Page 4 Vol 31, 2013 Mulleria). The main features of the leaf are grey-green glaucous ie white bloom and is often senescent (withered) at anthesis (full flowered). Of the T. nuda complex, T. megcalyptra is the most similar but its leaf is never glaucous and has a red base, as well as an earlier flowering time and habitat of plains and rock outcrops.

For more details on the other orchids in the T. nuda group see the post titled Those Blue Orchids Again … posted 30th January 2015 with the link to Jeanes article in the Muelleria

Those Blue Orchids Again …

Volume 31, 2013 of the Muelleria contains an orchid article by Jeffery A Jeanes. The title may be long – An overview of the Thelymitra nuda (Orchidaceae) complex in Australia including the description of six new species – but the subject is of interest to all of us who want to know our sun orchids, many of which are not always easy to identify.

 

By way of introduction, Muelleria is the Royal Botanic Gardens of Melbourne official research journal and has been published since 1955.

 

Though a technical article there is much to be gleaned for the ordinary reader, for instance the article contains a good description of the commonly used terms for describing the column for example stigma, trichomes, anther, post anther lobe, etc. This is helpful to know as the column structure is often the main feature of the plant used to identify the individual species. Naturally the key features of the T. nuda complex are covered comprehensively, as well as a brief discussion of the taxonomic history.

 

Another helpful section is the dichotomous key for all fifteen species described in the article. Of the fifteen species four are found in South Australia and are pictured below.  But to discover more read the article ……

Thelymitra nuda
Thelymitra nuda
T megcalyptra130927
Thelymitra megcalyptra
Thelymitra glaucophylla photographed by Robert Bates
Thelymitra glaucophylla photographed by Robert Bates

 

 

 

 

 

 

 

 

Thelymitra alcockiae
Thelymitra alcockiae

 

 

 

 

 

 

 

 

 

 

 

 

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)

Spotted Pink Sun Orchid – Beautiful, but Only a Hybrid

This week, a local radio station introduced a segment with the phrase “our rarest sun orchid” and that it was called Thelymitra irregularis or Spotted Pink Sun Orchid.  However it certainly is not our rarest sun orchid.

Thelymitra x irregularis is typically a hybrid pink spotted sun orchid
Thelymitra x irregularis,  Peter Watton, 2009

True, it is not common, but that is partly because it is a hybrid and, correctly speaking, the name should be written as Thelymitra x irregularis (the “x” indicates that it is a hybrid).

For a hybrid to occur, the two parent species need to grow in close proximity, the flowers need to open at the same time that the pollinator is visiting flowers, either to collect or to deposit the pollen and, in the case of self pollinating species, before the individual flower has pollinated itself.

The majority of hybrids are sterile, but occasionally some are fertile.  When hybrids occur the majority will only last a few years before disappearing although sometimes colonies are formed which may last for decades.  Hence, it is not usual to name hybrids, but the more common and recurring ones have been named formally.  T. x irregularis is one of them.

Several species of Thelymitra have been proposed as parent species of Thelymitra x irregularis.  Jeanes & Backhouse (2006) give T. ixioides and T. carnea as parents; Weber & Entwisle (1996) and Jones (2006) suggest T. ixioides and T. carnea and/or T. rubra; Bates & Weber (1990) state that in South Australia the parents are T. ixioides and T. rubra, but T. ixioides and T. carnea in the Eastern states; in contrast, Bates (2011) states that in South Australia it is a hybrid between T. juncifolia and T. rubra.  However, without detailed genetic studies or breeding experiments these all remain suggestions.

Due to the transient nature of hybrids and the conditions needed to produce them, the named hybrids are not common, but since the 1890s specimens of Thelymitra x irregularis have been collected in every decade, which suggest that this hybrid readily occurs.  The 71 specimens held in the Australian herbaria have been collected from four states – which gives a good indication of the distribution but not necessarily the frequency of occurrence.  See Australia’s Virtual Herbarium (AVH) for details.  The AVH lists 12 herbarium records for South Australia with specimens collected from the Adelaide Hills, the Barossa Valley, Kangaroo Island and near Naracoorte.

Thelymitra x irregularis
This Thelymitra x irregularis or Pink Spotted Sun Orchid was photographed by Peter Watton in 2009 near Macclesfield, South Australia

The botanical name “irregularis” refers to the description of the column.  With many sun orchids, it is often necessary to observe the column to distinguish one species from another.  In this instance the top of the column is irregularly toothed.  Retired Aussie has some very good photographs with one in particular showing the column detail.

 

Thanks to Juergan Kellermann, State Herbarium of South Australia for his help with this post.

References

Bates (2011). South Australia’s Native Orchids. DVD-ROM

Bates & Weber (1990). Orchids of South Australia.

Jeanes & Backhouse. Wild Orchids of Victoria, Australia

Jones (2006), Native Orchids of Australia, 2nd edn.

Weber & Entwisle (1996). Thelymitra. In: Flora of Victoria, Vol 3.

Australia’s Virtual Herbarium accessed 24th September 2014

 

July 2014 Winning Photograph

07 JB T antennifera sm

A photograph of a  yellow sun orchid is July’s winning photograph and was taken by John Badger.

It is not difficult to identify a yellow sun orchid because amongst all of the Australian Thelymitras there are only two true yellow sun orchids.  These are Thelymitra antennifera and the less common and very different, smaller T. flexuosa.

T. antennifera has a distinctive column with two reddish brown appendages resembling rabbit’s ears henc the connom name of Rabbit Ears Sun Orchid.  Another common name Lemon Sun Orchid refers to the faint but recognisable lemon scent produced by the flower but as to why it should ever have been singled out from the other sun orchids to be called Women’s Caps1, I cannot tell.

Prior to flowering, the leaf distinguishes this sun orchid from others.  Though having a red base like some of the other sun orchid, it is thin and rounded ie filiform and terete.  Further, the closed buds are dark pink with lemon yellow margins of the sepals.

It should be noted that both T. carnea and T. rubra can on rare occasions produce a pale yellow variety but they will have all the features of their respective species.  Also a T antennifera hybrid, T. x macmillanii, can on occasions produce yellow flowers.

References

  •  R. Bates (2011) South Australia’s Native Orchids DVD
  • David L. Jones (2006) A Complete Guide to Native Orchids of Australia
  • 1The Australian Zoologist 1945 – 1951 Vol II Issued by the Royal Zoological Society of  NSW http://biodiversitylibrary.org/page/39059910#page/7/mode/1up accessed 1st August 2014

Australian Orchids and the Doctors they Commemorate Part 4 of 20

Continuing Professor John Pearn’s article

Part 4

The first orchids scientifically named in the Pacific were species in the genus Thelymitra J.R.Forst. & G.Forst., a taxon raised and coined by the Forsters — the irascible Johann Reinhold Forster (1729–1798), and his son Georg Forster (1754–1794), who was 18 years old when they left on Cook’s second voyage of 1772 to 1775. The Forsters collected Thelymitra longifolia in the South Island of New Zealand in 1772 and published the name of the species in 1776. The Forsters described and named nine new species in what they termed the “Class of Orches” in the South Pacific. Georg Forster graduated in medicine in Vilna (now Vilnius, Lithuania) in 1784. Species of Thelymitra, which are known as the Sun Orchids, are found mainly in the south-west of Western Australia.

It should be noted that Thelymitra are found both in the east, central and the west of southern Australia.

May 2014 Winning Photo

05 PM T pulchemirra sm

Pauline Meyer’s winning photograph is a whole plant picture of Western Australia’s flamboyant Queen of Sheba Orchid.  It was taken at Eneabba, north of Perth and identified by a local as Thelymitra variegata but in consulting the books it would appear that it is the Northern Queen of Sheba, T. pulcherrima.  There are three species known as Queen of Sheba orchids in Western Australia – T. varigata, T. pulcherrima and T. speciosa.

T. variegata was originally named in 1839 by John Lindley but under the genus Macdonaldia.  In 1865 Ferdinand Mueller moved it to Thelymitra, later people began to separate it out to three different species* but it wasn’t until 2009 that Jeff Jeanes describeds T. pulcherrima and T. speciosa as distinct species from T. variegata.

All three species have a single thin spiral leaf and showy multi-coloured flowers.

T. pulcherrima and T. speciosa differ from T. variegata in the following points.

  • T. speciosa, begins flowering earlier, is a slightly shorter plant with fewer flowers (one, more rarely two) and although the flowers are a similar size to T. variegata they are even more colourful and the petals and sepals are distinctly different colours.
  • T pucherrima is similar in height to T. variegata but has smaller flowers with yellow, red, purple mauve sepals and pink purple mauve petals.  It too begins flowering earlier than T. variegata.
They all have distinct separate locations as reflected in the common names – Southern Queen of Sheba (T. variegata), Eastern Queen of Sheba (T. speciosa) and Northern Queen of Sheba (T. pulcherrima).  For some good images go to Retired Aussies or the Chookman
 
Finally there is one other species that is similar to these three and it is called Cleopatra’s Needle, T. apiculata.
 
  Thelymitra pulcherrima Theylmitra speciosa Thelymitra variegata
  Northern Queen of Sheba Eastern Queen of Sheba Southern Queen of Sheba
Distribution North of Perth between Lancelin and Dongara Between the Stirling Range and Condingup Between Perth & Albany with disjunct populations near Hyden
Flowering late June – early September late June – September August to September
Flower numbers 1 to 5 1 to 2 1 to 5
Flower height 150 – 350 100 – 200 mm 100 – 350 mm
Flower size 25 – – 35mm 30 – 50 mm 30 – 50 mm
Sepals Yellow, red, purple and mauve Yellow, red, purple and mauve Deep pink purple blotched
Petals Pink or purple and mauve Pink or purple and mauve Deep pink or purple and darker purple blotched
 
References:
Field Guide to the Orchids of Western Australia 2013, pages 425 & 427
I would like to thank Andrew Brown, co-author, for his help with this article.
 
* The name T. puchemirra is mentioned in the Western Australian Native Orchid Study and Conservation Group 2008 field trip report

April 2014 Winning Photo

Thelymitra crinita

With a common name of Queen Orchid, Thelymitra crinita is aptly named, for the flower has a quiet regal air of elegance and delicacy that would appeal to many people. Lorraine Badger who took this photograph was one of those people.

T crinita is a common Western Australian orchid that can be found from Perth around to Albany with a disjunct area near Esperance. Back in 1839, it was one of 60 orchids named by John Lindley in ‘Appendix to the first twenty-three volumes of Edwards’s Botanical Register together with A Sketch of the Vegetation of the Swan River Colony’ page xlix. Though the register is written in English the species description is in Latin, here reproduced for all those Latin buffs –

(214)  helymitra crinita; folio radicali oblongo apiculato glabro, raceme cylindraceo, floribus purpureis, cuculli laciniis lateralibus barbatis unguiculatis intermediâ fornicatâ emarginatâ dorso glanduloso-villosâ

On a recent visit to the South Australian State Herbarium, Michelle Waycott, Chief Botanist, explained that there is a strict botanical standard for describing a species. You may  be pleased to  know  that  at  the  18th  International  Botanical Congress in Melbourne, Australia in July 2011, it was determined  that  from  the  1st January  2012  it  was  no longer mandatory for descriptions to be in Latin only. English can now be used.