2017 July Winning Picture

July Winning Photograph

Corybas demenicus

July is Helmet Orchid Season; and the theme for the July Picture Competition.

In Australia, the genus Corybas in the broad sense (sensu lato) has four segregate genera; three on the Australian mainland (Corybas, Corysanthes & Anzybas) and one (Nematoceras) on Macquarie Island. All three mainland segregate genera were represented this month. Robert Lawrence’s, Anzybas unguiculatus; Margaret Lee, Corybas aconitiflorus with Jane Higgs, Lorraine Badger and John Fennell all entering Corysanthes diemenica. Lorraine also entered Corysanthes despectans; and John an image of Corysanthes incurva. The clear winner was Jane Higgs’ Corysanthes diemenica (synonym Corybas diemenicus).

The flower of Corybas sensu lato is characterised by a large dominant dorsal sepal and an equally dominant labellum. The other features associated with an orchid are not so obvious. The column is short and not visible. Even the ovary is barely visible whilst the other petals and sepals are but short thin filaments near the ovary. The base of the labellum wraps around to form a tube which hides the column; and the upper portion of the labellum folds back on itself and flares out. With this structure, two new features are introduced, the boss in the centre of the labellum and the auricles, two earlike openings formed from folding at the base of the labellum. Two growth features that are different from many other orchids are that the bud and leaf grow concurrently and once pollination has occurred the stem elongates so that the ovary can be raised up to 20 to 30 cms, thus allowing for seed dispersal.

Jane’s picture clearly shows these features as in the labelled image below.

Corybas demenicus

Thank you to Greg Steenbeeke for reviewing this article.

Reference

Backhouse, G, et al (2016) Bush Gems: A Guide to the Wild Orchids of Victoria Electronic version

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

Jones, D. L., A Complete Guide to Native Orchids of Australia Including the Island Territories. Reed New Holland

Jones, D. L.; Hopely, T; Duffy, S. M.; Richards, K. J.; Clements, M. A and Zhang X, Australian Orchid Genera an information and identification system. Electronic version, 2006, CSIRO

Rules of entry:

The subject matter must have something to do with Australian orchids.  Any format is acceptable including Photo shopped images, artwork, etc

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July 2016 Winning Picture

1607 sm RWL Corysanthes diemenicus.jpg

This month there were four very different species.  Two were from Western Australia, Pauline Meyers’ Caladenia longicauda and Lorraine Badger’s Thelymitra pulcherrima, and the other two from South Australia, Rob Soergel’s Bunochilus viriosa and Robert Lawrence’s Corysanthes diemenicus which was the winning picture.

Corysanthes diemenicus is a very common winter orchid but this one is unique as instead of one flower as is normal there are two!  So is it a new species? No, it is a freak; the technical terminology is teratologic.

Of the various plant families, the mint and orchid families (Theissen 2006) are well known for producing teratological plants, that is, plants that are grossly abnormal or deformed.  Bates (2011) divides such abnormalities into five categories – peloric, teratological freaks, monstrosities, colour variants and throwbacks.  All of them are congenital abnormalities which may be a result of unknown genetic malfunction or viral infection in the early developmental stages of the plant.  Based upon this division, Robert’s picture is a monstrosity.  This type of double flower is more likely to be found in self-pollinated plants for example Pterostylis foliata often produces more than one flower.

Most freaks are random, they come and go but peloric freaks are interesting.  An early meaning of peloria was an irregular feature that becomes regular (Walker 1879) but in the orchids the meaning has been narrowed to refer to an “abnormality of the labellum that is of a similar shape and colour of the petals” (Australian Orchid Genera 2006) or more precisely an abnormality of the inner tepal whorl (the petals) wherein the petals can take on the appearance (in part or full) of the labellum, or the labellum takes on the appearance of the petals.  One naturally occurring semi-peloric species is Calochilus imberbis. In recent years, orchid growers have cloned peloric freaks using a technique called mericlone to produce new cultivars eg Rhyncolaelia digbyana var. fimbripetala.

Freaks may be interesting but they are temporary so if you spot something unusual in the field look around at the surrounding orchids.  If there is only the one or two individual or one colony, then it’s likely to be an abnormality rather than a new species.

Thank you to Greg Steenbeeke for checking this article.

Reference:

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

Jones, D L et al, (2006) Australian Orchid Genera, an information and orchid identification system, interactive CD-ROM

Masters, M T (1879) Vegetable Teratology http://www.gutenberg.org/files/23354/23354-h/23354-h.htm accessed 3rd August 2016

St George, I (2007) Monsters, Freaks, Retrogrades and Primitives http://www.nativeorchids.co.nz/Journals/103/page5.htm accessed 3rd August 2016

Steenbeeke, G, personal communications

Theissen, G (2005) The proper place of hopeful monsters in evolution biology http://carah.sweb.cz/xx12295.pdf accessed 3rd August 2016