Red Beak Orchids
Red-beaks (Pyrorchis nigricans) are found in the southern section of the Reserve and there are a couple of large colonies. They have a rounded leaf that hugs the ground and their flower is produced from a tuber. They grow actively over autumn and winter and then flower over spring, from August to November – flowering is finished by October in the Reserve – and prefer moist heathland or heathy woodland on sandy soils.
The Red-beaks are pollinated by bee (speculated because of the presence of nectar and sweet smell) and via the production of new tubers.
Interestingly, they are supposed to flower after fire sometime in the previous 10 months. There has been no fire in this vicinity for a few years but they are growing in relatively open spaces in sandy soils. Jeanes and Backhouse (2006) explain their flowering is greatly stimulated in the presence of fire– indicated in Duncan’s ‘Response of orchids to bushfire’ (2012), reflecting on the effect of the 2009 Black Saturday bushfires on orchid growth in the subsequent growing periods.
Unlike Red-beaks, Bird orchids are sensitive to the effects of fire – also reflected in Duncan’s (2012) findings.
Bird Orchids (Chiloglottis species)
There are both spring and autumn flowering bird orchids in the Reserve. Records indicate both large flowering (Chiloglottis valida) and wasp orchids (Chiloglottis reflexa) have been seen, in the past.
The flower of this orchid has a large labellum – different sizes for different species – with a group of dark, shiny calli – stalks and buttons – with a particular arrangement – a ‘central, insectiform arrangement’ for the C. reflexa and something different for the C. valida.
It is this arrangement – labellum, calli – but mostly a particular scent mimicking a female thynnine wasp produced by the bird orchid that attracts a particular species of male thynnine wasp. Pollination occurs through this sexual deception and it is possible to tell one species from another by their particular pollinator.
These plants have active seasons of growth and dormancy and grow in areas with a seasonal climate.
Large bird orchid (C. valida)
These low growing bird orchids have been in flower since September. It is difficult to catch sight of these flowers and although described as ‘dull’, they have glowing purple red and green colouring that glistens in the light.
This variety of bird orchid grows particularly in moist montane and sub alpine regions, in damp shaded places in forest and woodland, but also in coastal areas. In the Reserve, there are two large colonies and scattered smaller groups of this orchid which produce two oval shaped (ovate) leaves in their early growing season from underground tubers. While large amounts of seed are produced, most increases in population occur from the underground tubers.
The flower’s calli arrangement – four to ten – occurs in the back two-thirds of the labellum and includes a taller stalked callus at the back, calli in decreasing size ranging to the front, and one broader button on the midline at the front, separated from the rest. It is the broader callus at the centre that the male wasp grasps. The labellum then collapses upwards, and the insect’s thorax picks up pollonia from the base of the column as it clambers out (see an image here), moving on to the next apparent female.
Lowland bird orchid (Chiloglottis species aff. valida 2)
These orchids (see Jeanes and Backhouse, 2006) flower from September to November, at the same time as the Large bird orchids in the Reserve. Their habitat is similar in terms of growing in damp shade in heath, forest and woodland. They have a slightly smaller labellum and have more calli in a different arrangement from the Large bird orchid.
The labellum has six to 14 stalked calli decreasing in size from the base to the apex.
Chiloglottis species – C.jeanesii??
This example seems similar to the Mountain bird orchid (Chiloglottis jeanesii). Jeanes and Backhouse (2006) explain the Mountain bird orchid is found in similar conditions to those of C.valida although it flowers from December to January. They also explain that orchid may be more extensive than originally thought, often growing with C. valida and may be locally common in suitable habitat.
A picture of the pollinator will be the way to tell for certain.
Sources and further resources
Bishop, T. (2000) Field guide to the orchids of New South Wales and Victoria. UNSW Press: Sydney
Duncan, M. – DSE (2012) Response of orchids to bushfire. Black Saturday Victoria 2009 – Natural values fire recovery program. http://www.depi.vic.gov.au/__data/assets/pdf_file/0019/203950/VBRRA-P27-web-rev.pdf
Jeanes, J. & Backhouse, G. (2006) Wild orchids of Victoria Australia. Aquatic Photographics: Seaford.
Jones, D.L. (1993) Genus Chiloglottis, PlantNET http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Chiloglottis
Mayfield, E. (2010) Flora of the Otway Plain and Ranges 1. CSIRO Publishing; Collingwood.
Pridgeon, A.M., Cribb, P.J. and Chase, M.W. (2001) Genera Orchidacearum: Volume 2. Orchidoideae. Oxford University Press: Oxford. [Google books]
Weston, P. H. (1993) Pyrorchis nigricans, PlantNET http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Pyrorchis~nigricans
Xu, S., Schlüter, P. M. and Schiestl, F. P. (2012) Pollinator-Driven Speciation in Sexually Deceptive Orchids. International Journal of Ecology, vol. 2012, Article ID 285081, 9 pages. http://www.hindawi.com/journals/ijecol/2012/285081/
There are some great sites and blogs on orchids. For a couple of good ones for great images and information about orchids:
Retired Aussies.com – http://www.retiredaussies.com/ – select ‘Victoria’
Anglesea orchids – http://www.angleseaorchids.com/