The Great Orchid Pretender

Actually there is more than one.

Frequently NOSSA receives a request to identify an orchid in someone’s garden.  Often, instead of an orchid (but occasionally there are orchids), it is the Ariasrum vulgare (common name Friar’s Cowl Lily or Cobra Lily).

Native to Asia and Europe, notably the Mediterranean and introduced to Australia, it is often mistaken for one of the flowers of the Pterostylis (Greenhood Orchids) or Diplodium (Shell Orchids).  Some have called it a Blackhood orchid others Snake Orchid.  It’s resemblance to the Greenhoods and Shell Orchids is superficial as they have none of the orchid features.  The dark purple hooded part is not the flower; it is a spathe (bract).  The flowers are minute hidden on deep down on the “tongue”.

The hood of the orchids is the combination of a deeply concave dorsal sepal interlocking with the lateral petals; and the fusing of the two lateral sepals.  Tucked away within the hood is the labellum (a modified petal) and the column (the reproductive organs of the flower).  The leaves of Ariasrum are quite large and distinctly different from any of the Greenhood orchids.

Friar's Cowl Lily 93RL
Arisarum vulgare amidst its large leaves
Pterostylis pedunculata 92RL
Pterostylis pedunculata (Maroonhood Orchid)
Diplodium robustum 92RL
Back view of a Diplodium robustum showing the dorsal sepal and two lateral petals that make up the hood of the flower

 

 

 

 

 

 

 

 

 

Diplodium robustum labellum and column 96HL
Looking into the Diplodium robustum – the labellum is the brown tip just visible at the front of the flower and the column is the brown white and yellow structure at the back
Pterostylis curta Labellum and column 92RL
Peering into the hood of a Pterostylis curta, the labellum is toward the front and the white and yellow structure to the back is the column
Friar's Cowl Lily open bract 93RL
The bract of the Arisarum vulgare has been split open to reveal the knobs which are the flowers. The flowers are so small a hand lens or microscope is needed to see them.

 

 

 

The time has arrived

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.

 

Corysanthes diemenica (Veined Helmet Orchid)
Corysanthes diemenica (Veined Helmet Orchid)

 

 

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

Orchid Walks at Mt Lofty Botanic Gardens

For the last couple of years, NOSSA has been conducting spring tours at the Mt Lofty Botanic Gardens, South Australia, showcasing our beautiful native orchids to visitors far and wide.  They have come from not only Adelaide but from interstate as well as overseas from such countries as America, Germany, England and many others.  If you are planning to be in Adelaide during spring, then consider joining one of our walks, but for those who cannot attend here is a video for you.  So watch and enjoy …….

 

Australian Orchids & the Doctors they Commemorate Part 14 of 20

Richard Sanders Rogers (1862 – 1942)

An Adelaide physician, doctor-soldier and forensic pathologist who described 82 new orchid species (66 from Australia).

Orchids

Diplodium rogersii (= Pterostylis rogersii) or Curled Tongue Shell Orchid

Prasophyllum rogersii or Marsh Leek Orchid

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