2017 August Winning Picture

The following article  appeared in the Native Orchid Society of South Australia Journal September 2017 Volume 41 Number 8. It is a longer and expanded version of the article as  George Bentham was one of most influential botanists of the 19th century making it difficult to summarize his life. Even this article barely scratches the surface of this most interesting man.

The theme for the August competition was Striped or Blotched orchids.

1708 JF Thelymitra benthamiana cr

Blotches or stripes, which one? An interesting collection was entered. Representing the stripes were John Fennell’s Dipodium pardalinum, Shane Grave’s Cyrtostylis robusta labellum, Helen Lawrence’s Thelymitra cyanea, Robert Lawrence’s Diplodium dolichochilum and Lorraine Badger’s T. campanulata. There were less blotches; Ricky Egel’s Diuris pardina and John Fennell’s T. benthamiana.

T. benthamiana (Leopard Sun Orchid) is a popular orchid to photograph and it is not surprising that it is again (see April 2016) a winner in our competition. It was named after the Englishman George Bentham (1800 – 1884) one of the foremost and influential systemic botanists of the 19th century. At about the age of 16 or 17 years he was introduced to botany, and despite training as a lawyer, he devoted his life to the study of botany.

Though never visiting Australia, he produced the world’s first completed continental flora, Flora Australiensis, a seven volume work produced over 15 years (1863 – 1878). As monumental as this was, at the same time he was working on his greatest work, co-authored with Joseph Dalton Hooker, Genera Plantarum (1862 – 1883) in which is introduced the Bentham & Hooker system of plant classification. This system is still in use by many herbaria around the world. It involved the study of actual plant specimens, a practice which Bentham used himself. For instance, in the production Flora Australiensis, he would examine, critique and describe over a 1,000 species each year.

This practice harkens back to his early days when in his Flora of the French Pyrenees (1826) he adopted the practice of citing nothing second-hand. He never deviated from this. It did help that he was able to read in fourteen modern European languages plus having a good command of Latin, the language used for many botanical writings. This enabled him to access original material which he did by visiting every European herbarium when preparing for his first major work Labiatarum Genera et Species (1832 – 1836).

A shy and unassuming man, Bentham had the respect of the botanical world as was reflected in the various awards he received. Described as a genius, [a man of] indefatigable industry, the premier systematic botanist, he considered himself an amateur botanist, never a professional, even though he donated his extensive collection of more than 1,000 specimens to Kew Gardens in 1854 where he worked full time until his death in 1884. Bentham lived in, and contributed to, the transitional period from the dominance of the gentleman botanist to the government being responsible for collections of national and scientific significance.

He was responsible for introducing into orchid taxonomy (1881) a new classification recognising Subtribes, which precedes Genus in the classification system; introduced the word ‘orchidologist’ to the world in his Notes on Orchideae, 1881. Although there is only one Australian orchid named after Bentham, he has a whole genus of 29 species named after him: Benthamia which is endemic to Madagascar, Mauritius and Reunion. Worldwide, Bentham was directly involved in naming over 200 orchid taxa.

Thanks to Greg Steenbeeke for critiquing this article.

Reference

N. T. Burbidge, ‘Bentham, George (1800–1884)’, Australian Dictionary of Biography, National Centre of Biography, Australian National University, http://adb.anu.edu.au/biography/bentham-george-2979/text4345 , published first in hardcopy 1969, accessed online 29 August 2017.

George Bentham Retrieved August 31, 2017 https://en.wikipedia.org/wiki/George_Bentham

The Taxonomy of the Orchidaceae Retrieved 31 August 2017 from https://en.wikipedia.org/wiki/Taxonomy_of_the_Orchidaceae

Bentham, George (DNB00). (2012, December 29). In Wikisource. Retrieved August 31, 2017, from https://en.wikisource.org/w/index.php?title=Bentham,_George_(DNB00)&oldid=4211195

Bentham and Hooker system of Classification. Accessed August 31, 2017 from http://vle.du.ac.in/mod/book/print.php?id=13270&chapterid=29150

Notes on Orchidaea (Journal of the Linnean Society)

English Oxford Living Dictionary. Accessed 31 August, 2017 from https://en.oxforddictionaries.com/definition/orchidologist

 

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Orchid Basics – Labellums and Columns

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.

Sun Orchid

Thelymitra – though the labellum is almost indistinguishable from the other petals and sepals, the column is quite complex.

Hyacinth Orchid

Dipodium or Hyacinth Orchid

Greenhood

Pterostylis or Greenhoods – generally a simple labellum with the column hidden well back into the hood.

Spider Orchid

Arachnorchis (syn Caladenia) can have quite varied and complex, mobile labellums

Helmet Orchid

Corybas or Helmet Orchid – the labellum dominates and the column is hidden deep inside the flower.

Donkey Orchid

Diuris or Donkey Orchid – the labellum is divided giving the appearance of more than one structure.

*Bates and Weber Orchids of South Australia 1990

 

2017 June Winning Picture

1706 sm RWL Thelymitra grandiflora 10

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

Reference

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

Gleanings from the Journals: Terrestrial Potting Mixes

The following article by Les Nesbitt was published in May 2017 Native Orchid Society of South Australia Journal Volume 41 No 4. The article relates to Australian Native Orchids.

Suggested potting mixes for potted native terrestrial orchids have changed greatly over the years as some ingredients such as peat moss have become too expensive or difficult to obtain. Basic requirements are that the mix should be free draining yet retain moisture and should have an organic component that breaks down slowly and does not go mushy in winter. Most species are not too fussy and will grow in a variety of mixes.

Those tubers that desiccate in summer do better in a heavy mix that contains clay. Examples are Diurus behrii, D. punctata and Pterostylis nutans.

Tubers that rot easily in wet soil in Spring prefer an open coarse sandy mix. An example is Thelymitra antennifera.

A dry mix containing a higher proportion of sand is usually recommended for Caladenia and Glossodia species grown in pots. In contrast these orchids grow in clay soil on my property in the Adelaide Hills but there excess water can run off. In pots, excess water has to drain through the potting mix.

An organic component is vital to feed orchid fungi.

Some Basic Ingredients:

  • Washed sand with rounded particles. (Not sharp sand as this sets hard in summer.)
  • Soil (sandy loam, clay based loam, mountain soil)
  • Native seedling mix (Bark based – sieve to remove splinters)
  • Native potting mix (can be sieve* to remove larger particles)
  • Chopped and sieved* gum leaves
  • Perlite or isolite (but will make tubers harder to identify at repotting time)
  • Composted leaf mould & buzzer chips (but needs to be gathered now for use next summer)
  • Cauarina (She-oak) needles chopped for surface mulch

Some Suggested Potting Mixes

  1. ANOS-Vic dry mix – 2 parts coarse sand, 1 part coastal sandy loam, 1 part composted buzzer chips, 1 part leaf mould
  2. 100% native potting mix. (Works for drought resistant tubers, viz. Pterostylis curta & P. pedunculata)
  3. Native potting mix (sieved*) and isolite
  4. Native potting mix and sand
  5. Les Nesbitt’s current mix of 50% sand, 20% hills soil, 25% seedling potting mix (sieved), and 5% chopped & sieved* string bark gum leaves.
  6. Dry mix, 50% coarse sand, 25% perlite & 25% native potting mix
  7. Heavy mix, 50% clay soil, 30% sand and 20% organic matter

* Use a 5mm sieve

thelymitra-plants-1.jpg

Thelymitra in cultivation

UPSIDE UPSIDE DOWN

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.

ld-caleana-major

Caleana major, Knott Hill NFR Photographer: Leo Davis

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.

ld-thelymitra-benthamiana

Thelymitra benthamiana, Scott Creek CP; Photographer: Leo Davis

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.

ld-arachnorchis-stricta

Arachnorchis stricta, Sherlock; Photographer: Leo Davis

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.

ld-cryptostylis-subulata

Cryptostylis subulata, Stipiturus CP; Photographer: Leo Davis

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?

ld-cryptostylis-subulata-with-labellum

Cyrtostylis subulata with labellum lifted; Photographer: Leo Davis

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?

Mad Dogs and …. Orchidologists

Mad dogs and Englishmen are not the only ones to go out in the  midday sun.  For orchidologists to see Sun Orchids flowering, then it is out into the midday sun on a hot day because that is when they open.  There is no point going much before 11am and by 2pm most are closing and no point going out on a cool or windy day.

1604 sm CC T benthamaniana

But for those who don’t want to  go out (or cannot get out) into the midday sun, here is a video to be viewed in the cool of the shade.

This video features the Leopard Sun Orchid (Thelymitra benthamiana) an uncommon Sun Orchid in South Australia.  Unlike many sun orchids which requires a view of the flower to confirm identification, this one can be identified by the leaf alone.  At the beginning of the video take note of its distinctive leaf.

Thelymitra benthamiana

CULTURE OF SLOW MULTIPLYING (SM) TERRESTRIALS

Pots of Thelymitra nuda cultivated by Les Nesbitt

Thelymitra nuda

The second fact sheet in Terrestrial Culture notes is about Slow Multiplying Terrestrials.

FLAGBEARER SPECIES: Thelymitra nuda

Diuris, Pterostylis and Thelymitra. They are more expensive because they have to be raised from seed in flasks. SMs are not so easy because there is less room for error. A few have a near zero increase rate and will fade away unless additional plants can be produced to make up for occasional losses from predators and disease.

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. Pterostylis leaves are usually the first to appear in March/April followed by Diuris and Thelymitra in April/May. 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: Australian terrestrial orchids are easy to grow. 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. Sun loving species (Diuris, Thelymitra & Rufa group Pterostylis) prefer a brighter location for good growth.

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. The spring flowering species like higher light intensities at flowering time and flowers may have pale colours if placed in heavy shade, even temporarily, when flowers 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.

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.

POLLINATION/SEEDCOLLECTING: Flowering plants are hand pollinated and the seed collected just before the pods split open and the dust-like seed blows away. The seed is sprinkled on pots of mother plants at Easter or flasked.

REPOTTING: Repot every second year in half new mix. Repotting is normally done between November and January. The best results are obtained if the tubers are repotted in half fresh soil mix each second year. A suitable soil mix is 40% loam, 50% sand and 10% organic matter with a little blood and bone fertiliser added. A 5 mm sieve is a useful tool for separating tubers from soil. Replant the dormant tubers with the tops 20 mm deep. Cover the soil surface with a mulch of sheoak needles, chopped to 20 – 50 mm lengths, to prevent soil erosion & aerate under the leaves.

INCREASING PLANT NUMBERS: The pull-off-the-tuber method can be used with some diuris and Pterostylis species to double plant numbers annually. The pots can be knocked out and the tubers examined in Summer without harm.

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.

FERTILIZING: SMs will benefit from weak applications of folia feed in the early growth stages.

OTHER CULTURE NOTES:

 

NB: IT IS ILLEGAL TO TAKE PLANTS (WHOLE PLANT, FLOWERS, SEEDS AND TUBERS) FROM THE WILD

Sun Orchid Observations – Extract from Start With The Leaves

In the past week there has been some Facebook conversation on the identification of some Thelymitra (Sun Orchids) here in South Australia.  Sun Orchids can be problematic particularly when there is only one photograph.  If the photograph has a clear view of a diagnostic feature, then identification becomes simpler but there are many species for which careful observations are necessary to determine the correct one.  This is important when considering some of the complexes, eg T. nuda and T. pauciflora which have several similar species.  Colour is not always helpful as there can be either variation in colour or no colour at all.  Further complicating identification is that Sun Orchids readily hybridise, far too easily sometimes!

When Robert Lawrence wrote his book, Start With the Leaves, he realised the difficulty in identifying some orchids, so he included a checklist of observations.  The checklist is extensive but was developed to be used with the electronic version of South Australia’s Native Orchids by RJ Bates which covered all the known South Australian orchids in 2011.

 To assist in orchid identification, take as many photographs as possible, showing different parts of the plant and habitat from as many different angles.  But remember, photograph the typical plants.

Which is which

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

At the bottom of the post is a picture showing the parts of the flower.

The following extract is from pages 185 – 187

Thelymitra species (Sun Orchids)

Habitat features

Describe the habitat where the plants are found

Is the species confined to swamps or very moist sites?

Was the site burnt in the last year or two?  (Find out when if possible)

Are the plants restricted to a particular habitat or is there a range of situations where it grows?

Has it multiplied following disturbance?

Does it prefer wet or dry sites?

What other plants are growing with the orchids, including the trees forming the canopy?

Number of plants

Estimate the number of plants or describe the distribution of the plants at the site

Do plants occur in small clumps?

Do plants occur in colonies and if so how large are they?

Size of the plant

What is the height of the flower stem and width of the flower stem?

Leaf features

What are the length, width and shape of the leaf?

Is the leaf flat, channelled (u-shaped) or tubular in section?

Does the leaf change shape along its length?

Does the leaf have parallel ridges?

Is the leaf thick and fleshy or thin and papery?

What colour is the leaf?

Does the leaf have a reddish base and is the red colouration in parallel lines?

Are there any hairs on the leaf and are they confined to the margins?

Is the leaf rigid and upright or is it weak at the tip and falling under its own weight?

What is the tip of the leaf like and does it have a pointed apex?

Are the leaves shiny or to they have a powdery covering?

Stem features

What is the diameter of the stem?

What is the colour of the stem?

How high is the fistula, the point the point where the stem separates from the leaf?

Sterile bracts

(Bracts are leaf-like structures along the flowering stem)

How many bracts are there on the stem (ie those that are not immediately below a flower)?

How long is each of these bracts?

What colour are the bracts?

Are the bracts tightly or loosely wrap around the stem?

Fertile bracts

(Fertile bracts are leaf-like structures at the base of each flower)

How long are the bracts?

What colour are the bracts?

Ovary features

(The ovary is the structure immediately below the petals and sepals that becomes the seed capsule after the flowers are pollinated)

What colour are the ovaries?

How long are the ovaries?

How wide are the ovaries?

Flower features

What time of the year are the flowers open

What is the length and width of each flower?

Do the petals and sepals open widely, or does the flower remain almost closed?

What colour are the petals and sepals?

Do the petals have spots or darker coloured veins?

Is the labellum larger or smaller than the other segments (petals and sepals)?

Are segments rounded, pointed or cup shaped?

What colour is the outside of the buds?

What conditions are required for the flowers to open?  Are they only open in hot, humid conditions?

 Column features

What colour is the main part of the column?

Describe the post-anther/mid-column lobe

Is there a tubular structure on the top of the column?  What colour is this and does it have a collar of a different colour?

Does the lobe have a cleft in the apex and how deep is this?

Does the column have lateral lobes (arms) reaching in front of the column?

Are there trichomes (hair-like structures) in a mop or toothbrush arrangement?

Is there a sharp bend in the column arms?

If there is not a tubular lobe, are there three levels of structures on the column?

Are there papillae (rows of narrow bumps)?  How many and what colour are they?

What colour is the crest, if present?

Fragrance

Describe the fragrance of the flower or whether there is none

Thelymitra Flower Details

Related Articles

Thelymitra (Sun Orchid) Columns

What Orchid is This? How Photos can Help! Part One of Two Parts

What Orchid is This? How Photos can Help! Part Two of Two Parts – Comparing Crytostylis reniformis and C. robusta

Spotted Pink Sun Orchid – Beautiful but Only A Hybrid  T. x irregularis

November 2015 Winning Picture includes T. x truncata and T. x irregularis

Those Blue Orchids Again – An Overview of the Thelymitra nuda complex

 

April 2016 Winning Picture Competition

1604 sm CC T benthamaniana

Thelymitra benthamiana; Photographer: Claire Chesson

Five entries were received, again spanning the country from east to west. John Badger entered a Chiloglottis reflexa recently photographed in Tasmania, Pauline Meyers an unidentified Western Australian Spider orchid, Judy Sara had two entries from the latest field trip, Eriochilus collinus (previously phrase name Adelaide Hills) and Leporella fimbriata and Claire Chesson’s Thelymitra benthamiana.

T. benthamiana, the winning picture, is a beautiful sun orchid that is found across the southern Australia from Western Australia through South Australia to Victoria and Flinders Island. More common in west than elsewhere it is the only one of the seven species in the T. fuscolutea complex to be found in the east.

It would appear that this complex has been a problematic as indicated by Jeanes (2006) in his article Resolution of the Thelymitra fuscolutea (Orchidaceae) complex of southern Australia published Muelleria; the Royal Botanic Gardens of Victoria research journal.

Since the early days confusion, which persisted into this millennium, has occurred. In 1871 Reichenbach recognised 3 species one of which was T benthamiana but Bentham after whom the orchid was named disagreed and consider it but a synonym of T. fuscolutea. There were many twists and turns in the names but in effect, for over a hundred years, most authors followed Bentham’s taxonomy rather than Reichenbach’s until 1989 when Mark Clements after studying the drawings, literature and orchid type material came to the same conclusion as Reichenbach that T. benthamiana was a distinct species from T. fuscolutea. Since then, authors have followed Reichenbach/Clements taxonomy.

Over the decades, the number of species in this complex varied considerably. By 1938 three separate species were recognised, but between then and 1989 it fluctuated between recognizing one, three and four species and in 1998 the orchidologist were considering a possible seven species.  These were all confirmed and named in Jeans’ 2006 paper. Today, according to Orchids of Western Australia there is potentially an eighth member in this group.

Jeanes highlights some of the issues involved in determining which species is which. Some of the issues are lack of accurate/detailed information such as location, type of terrain, habitat, surrounding plants, date of collection, etc. Dried specimens by themselves are inadequate as important features may be lost in the drying process.

This complex is but an example of a widespread problem across many of our Australian orchids indicating not only the need for careful observations in the field but meticulous record keeping that others can access.

References

Jeans J A, Resolution of the Thelymitra fuscolutea R. Br. (Orchidaceae) complex of southern Australia. Muelleria 24: 3-24 (2006)

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

Thank you to Juergen Kellermann, (senior botanist for the State Herbarium) for critiquing this article.

Are there any orchids growing in the desert?

Think of deserts and the image is that of a bleak barren landscape with little to see but this is not so.  The conditions are harsh but there is a myriad, though not an abundance, of hardy fauna and flora if one but looks closely.

But concerning orchids – No orchids have been found in true deserts…..  They also appear to be absent from the arid mountains of the far north-west, or at least no-one has ever found orchids there.

Orchids need moisture and so they do not grow on unstable soils such as dry sand-hills, gibber plains or the many saline areas of the far north but on the desert fringes there are micro-climates where the moisture, humidity and soil structure is  just right (to quote Goldilocks) for orchids.  This micro-climate is created by [s]hrubland  [which] is … [an] … important dryland orchid habitat. Besides providing shade and shelter for the orchids, shrubs like the many species of wattles, Acacia and hop-bush Dodonea drop fine leaves which help to hold the soil together and slowly break down into humus rich with nutrient and water storing capability. These shrublands usually form in soils too dry or shallow for trees. Orchids of course have no need for deep soils as they are shallow rooted. 

Robert Bates Semi-arid Shrubland.jpg

Semi-arid Shrublands, Flinders Ranges

Of the five desert botanical regions, the Eastern region contains the most number of species with over a dozen species.

Botanical Regions Map

Colour added to indicate the desert regions (in red)

Orchids of the Eastern Region – this region is from the east of the Flinders Ranges to the New South Wales border and includes the Olary Spur and Lake Frome.

Arachnorchis toxochila – Dry Land Spider Orchid or Bow Lip Spider Orchid.
Corunastylis tepperi – Mallee Midge Orchid
Diplodium robustum – Common green shell-orchid.
Hymenochilus pagophilus – Mountain Shell-orchid
Microtis eremaea – Desert onion orchid
Microtis frutetorum – Common woodland onion orchid.
Oligochaetochilus bisetus species complex, Rusty rufous-hoods

Oligochaetochilus sp. Blue-bush Plain – Blue Bush rufous-hood (O. bisetus complex)

Oligochaetochilus sp. Outback – Outback rufous-hood (O. bisetus complex)

Oligochaetochilus cobarensis – Little desert rufous-hood
Oligochaetochilus sp. Crossed Sepals Bibliando rufous-hood. (O. hamatus complex)
Oligochaetochilus sp. Bimbowrie Bimbowrie Rufoushood (O boormanii complex)
Oligochaetochilus linguus – Swept-back Rufoushood

Oligochaetochilus sp. Old Boolcoomatta Large-lip rufous-hood (O. linguus complex)

Oligochaetochilus sp. Quartz – Quartz hill rufous-hood (O. linguus complex)

Oligochaetochilus sp. Slender desert – Slender Desert rufous-hood (O excelusus complex)
Undescribed not within any other Oligochaetochilus complex

Oligochaetochilus sp. Canegrass – Desert Sand-hill Orchid.

Oligochaetochilus sp. Oratan Rock – Diminutive rufous-hood

Oligochaetochilus sp. ‘Mt Victoria Uranium Mine’ – Uranium rufous-hood

Prasophyllum odoratum – Scented Leek-orchid

Prasophyllum sp. Desert Desert Leek-orchid (P. odoratum complex)

The Gairdner-Torrens region includes, besides the salt lakes it is named after, the Gawler Ranges and the southern part of the Great Victoria Desert.  Though not as many species as the Eastern region, it contains some different species including a Sun Orchid.

Thelymitra megcalyptra

Thelymitra megcalyptra

Arachnorchis interanea – Inland Green-comb Spider Orchid
Arachnorchis toxochila – Dry Land Spider Orchid or Bow Lip Spider Orchid.
Hymenochilus pagophilus – Mountain Shell-orchid
Hymenochilus pisinnus – Tiny Shell-orchid
Jonesiopsis capillata – Pale Wispy Spider Orchid
Linguella sp. Hills nana – White haired little-greenhood.
Microtis eremaea – Desert onion orchid
Oligochaetochilus ovatus – Ovate Lip Rufoushood
Oligochaetochilus xerophilus – Desert rufous-hood
Prasophyllum sp. Desert Desert Leek-orchid (P. odoratum complex)
Thelymitra megcalyptra – Scented or Dryland Sun Orchid

Third of this group is the Nullabor region.  Consisting of flat treeless limestone plains, this area, surprisingly, has two species both of which have been found close to the coast.

Urochilus sanguineus – Maroon banded greenhood
Corunastylis sp. Intermediate – Halbury Midge Orchid (C. rufa complex)
Urochilus sanguineus

Urochilus sanguineus

The final two regions Lake Eyre and North-Western contain the vast expanses of desert of the far north of South Australia.  Definitely not a place to find orchids yet one specimen has been collected from each of these two regions.

Oligochaetochilus sp. Everard Range (L. Scott 173), Mimili Orchid (possibly O. woollsii complex) from North-Western Region.

Oligochaetochilus sp. Gammon Range (O excelusus complex) from the Lake Eyre region.

It is unusual to find orchids in the desert because they only grow when there have been good winter rains which isn’t very often.  But nevertheless, here in South Australia we have over 20 possible species – an astonishingly high number for such a harsh area!

Reference:

Bates R J ed, South Australia’s Native Orchids, 2011 Native Orchid Society of South Australia

Map adapted from Flora of South Australia, Fourth Edition, 1986