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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