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

 

Q&A: How do I deal with mould in my orchid flasks?

Question:

I have recently been learning about propagating orchid via flasks but I have mould in some of the flasks.

Orchid Seeds in flask with mould
Flask with orchid seeds and mould

There is mould in the flask with orchid seeds and also in the flask with Diuris tricolour in bulbs.  The bulbs are almost ready for deflasking.

Diuris tricolour in flask
Flask of Diuris tricolour (no mould) – these will be deflasked later this year.

 

What can I do?

Answer:

With a home laboratory, no matter how careful one is, mould can still contaminate the jars of agar. If mould occurs when the orchids are still in seed, then the whole jar needs to be discarded.  The seeds will not survive.

With the Diuris flask, as they are almost ready for deflasking, pot them out straight away. This needs to be done within 10 days of the mould appearing. The weather (March, 2017, South Australia) is still a little too warm but if left in the flask, the plants will die.  Potting them out may give them a chance of survival.

When deflasking, it is important to rinse all the agar off the bulbs before potting on as normal. Once potted, it could help to cover the pot with a cut down clear drink bottle with the lid removed. This will allow some air to circulate. Keep the pot in a shady spot.

Diuris tricolour in pot with bottle top cover
Potted Diuris tricolour with protecting bottle cover

Will it survive in the pot? Hopefully it might but at least the plants have a better chance of survival then if left in the flask where it would surely die.

 

2015 October Winning Photo

Diuris brevifolia (Late Donkey Orchid)
Diuris brevifolia  (Late Donkey Orchid)

Again this month was a varied selection of species with Pauline Myers’ Caladenia chapmanii (WA), Claire Chesson’s Thelymitra rubra, Jenny Pauley’s hybrid of Arachnorchis brumalis x conferta, David Hirst’s Caladenia discoidea and the winning entry, Rosalie Lawrence’s Diuris brevifolia.

This strikingly yellow flowered donkey orchid endemic to South Australia is listed as Endangered. Its range was once quite widespread in the southern Adelaide Mt Lofty Range region but now it is now restricted to pockets on the Fleurieu Peninsula and western Kangaroo Island in Heathy Woodland, Wetland and Riparian habitats.

There is interest today in cultivating orchids for conservation or ex situ conservation. With the reduced range of this species, can it be cultivated and thus continue to ensure its survival as a species? Some sources seem to suggest that it is an easy plant to cultivate, and some Diuris are easier than others, but Les Nesbitt points out that he has some plants from a rescue dig several years ago and that they have not multiplied very much in that time. This suggests that they may be dependent on a specific fungi. Though it has not been hugely successful in cultivation, it is worth noting that it has been used to produce hybrids with several other Diuris.

Reference

Bates, R. J. (2011) South Australia’s Native Orchids NOSSA DVD, Adelaide

Nesbitt, L personal communications

Adelaide and Mount Lofty Ranges South Australia Threatened Species Profile Fact Sheet – Diuris brevifolia

2015 May Winning Photograph

05 sm PM Diuris hazeliae

Western Australia produces a lovely array of orchids and so it is not surprising to find in NOSSA photograph competitions that when a Western Australian species is entered it can often be the winner. This month was no different with Pauline Myers beautiful picture of a mass of Diuris hazeliae which was kindly identified by Andrew Brown.

This species has only recently been named in 2013 and as a result finding information was a challenge. Obviously there was no information in Jones Native Orchids of Australia (2006); and surprisingly the definitive Field guide to the Orchids of Western Australia (2013) A Brown et al did not appear to have any information.

But

  • the Western Australian Herbarium’s FloraBase (Western Australian Flora), has a map of distribution which is roughly a diagonal line from east of Geraldton to the north of Esperance. It is not listed as threatened.

    Distribution of Diuris hazeliae.  Map taken from the Western Australian Flora Base
    Distribution of Diuris hazeliae. Map taken from the Western Australian Flora Base
  • the Western Australian Herbarium lists the species as one of 59 new taxa added to their plant census in 2014.
  • from the Atlas of Living Australia it can be deduced that the flowering time is mainly August and September and is likely to be found in various types of shrublands margins including Eucalypt and mallee woodlands and appears to be mainly associated with rocky or granite outcrops.
  • and the National Species List APNI/APC yields the information that it was named after Hazel King, plant collector and conservationist with a special interest in orchids and was previously known by the phrase name Diuris ‘northern granite’ with a common name of Rosy-cheeked Donkey Orchid. It was found in a granite outcrop on her property Tampu (north of Beacon).

Fortunately Andrew Brown was able to help with extra information. It is listed in his book (page 212) but under the phrase name Diuris sp. Eastern Wheatbelt (Yellow Granite Donkey Orchid). Diuris sp. Northern Granite was found to be the same species and so the use of that name was discontinued but it does remain a synonym for Diuris hazeliae.

The following description is information updated from his book “Field Guide to the Orchids of Western Australia”

Diuris hazeliae D.L. Jones & C.J. French (yellow granite donkey orchid)

Flowering: August to September.

Description:

A common, inland donkey orchid 100 to 300 mm high with two to three basal leaves 50 to 150 mm long by 5 to 10 mm wide and up to seven predominantly yellow, brown marked flowers 20 to 40 mm across. Flowers are characterised by their broad petals, very broad dorsal sepal, narrow, reflexed, usually crossed lateral sepals and tri-lobed labellum with broad, spreading lateral lobes and a broad, flattened to convex mid lobe.

Distribution and habitat:

Found between Mullewa, Salmon Gums and Balladonia, growing in shallow soil pockets on granite outcrops and along drainage lines below rocky breakaways.

Notes:

Named in 2013 from specimens collected at Tampu, north of Beacon in September 1997. The species often forms very large colonies on granite outcrops.

Distinctive features:

Inland granite and breakaway habitat.

Very broad dorsal sepal.

Diuris hazeliae is part of the Diuris corymbosa complex of which, in 2013, there were only 10 of the 26 Western Australian species formally named. This situation has now changed with 14 now formally named. As a final word, Diuris orientis is South Australia’s only member of this complex.

More images of this species can be seen on Retired Aussies website http://www.retiredaussies.com/ColinsHome%20Page/OrchidsWA/Diuris/Diuris%20sp%20northen%20granite/Diuris%20sp%20northern%20granite.htm

 

References – All websites accessed on 29th May 2015-06-04

https://florabase.dpaw.wa.gov.au/science/nuytsia/755.pdf

https://florabase.dpaw.wa.gov.au/browse/profile/44161

https://biodiversity.org.au/nsl/services/api/instance/apni/772000

Jones, Native Orchids of Australia and its Territories (2006)

Brown, Field Guide to the Orchids of Western Australia (2013)

March 2015 Winning Photograph

Three winners; three very different orchids but that is typical of Australian Orchids, there is no one species that you can point to and say that is a typical orchid as illustrated by the the winners which were Sarchochilus falcatus (Kris Kopicki), Diuris palustris (David Mangelsdorf) and Simpliglottis valida synonym Chiloglottis valida (Pauline Meyers).

Sarchochilus falcatus (common name Orange Blossom Orchid) is an epiphyte.  03 KK sm Sarcochilus falcatus Mt Banda BandaThe cultivated plant in this photo originated from the Blue Mountains just north of Macquarie.  Epiphytic/lithophytic orchids are found across northern Western Australia through the Top End and from a narrow band down the east coast to Tasmania; that is in all States except South Australia.  About a quarter of Australian orchids are epiphytes and despite the widespread distribution, 90% of epiphytic orchids are found primarily in the rainforests of northeastern Queensland.

S. valida (common name Large Bird Orchid or Frog Orchid) 03 sm PM Chiloglottis validaand D. palustris (common name Little Donkey Orchid or Cinnamon Donkey Orchid) are terrestrial, the larger of the two orchid groups.03 sm DM Diuris palustris  Terrestrials are mainly found across the southern part of the continent with some occurring in the north and tropics.  Their optimal habitat is the various types of sclerophyll forests found in Australia.

There is some distribution overlap but the two groups mainly occupy different habitats.

Concerning the habitat of the two terrestrials, S. valida ranges from tall moist closed forest to shaded places of drier open forests to sphagnum bogs and in the mature pine plantations of the South East.  Whereas D. palustris occurs in wet and swampy habitats in the Eastern states (hence it is named from the Latin palustre meaning swampy), in South Australia it is not so. Instead it is found in open terrain of grassland, grassy woodland, mallee and shrubland.

Some Odd Facts:

S. valida is a small ground hugging plant the scape (flowering stalk) of which elongates to 10cm or more after pollination.  Click on this video link to see these plants ‘talking’.  In New Zealand it is described as a vagrant having been introduced from Australia.

Sarchochilus falcatus is the most common and widely distributed species of this genus in Australia.  Occassionally it is lithophytic (grows on rocks). Though it had been rated Endangered and downgraded to Vulnerable in 2005, it is still under major threat from illegal collecting, trampling, water pollution, weeds and fire. New Zealand has epiphytes and the common name for them is Perching Orchids.

D. palustris is uncommon in South Australia and Tasmania; and rare in Victoria.  D. palustris was one of the subjects painted by Adelaide colonial artist and cartoonist Margaret Cochrane Scott in 1890s who had an affinity for native orchids.

 

References:

All internet references accessed on 31st March 2015

https://www.anbg.gov.au/cpbr/cd-keys/orchidkey/html/intro-c_habitat.html

http://anpsa.org.au/APOL19/sep00-1.html

http://www.nativeorchids.co.nz/Species/Simpliglottis_valida.html

http://data.rbg.vic.gov.au/vicflora/flora/taxon/4cebc1f9-38da-4c61-9c3c-37c2efc6da32

Mark Clements The Allure of Orchids 2014

http://www.iucnredlist.org/details/44392876/0

Bates 2011 South Australia’s Native Orchids DVD