Orchids are found in a wide range of habitats. One such habitat is the littoral zone or more simply the seaside. The following information is taken from the NOSSA’s CD/DVD South Australia’s Native Orchids 2011.
The Littoral Zone
Many orchid species have a linear distribution following the coastline. Here on the leeward side of sandhills the air is usually moist and mild, few frosts occur so close to the sea and sea-fogs in winter will cause water to drip into the sand which easily soaks up both the moisture and the extra nutrients provided by sea-spray. Some of the best known coastal orchids include the gnats Cyrtostylis robusta, pink fairies Caladenia latifolia, coast onion-orchids, Microtis arenaria and coastal helmet orchids Corysanthes expansa as well as C. despectans. All of these are colony forming species, mostly because the windblown sand would soon cover ‘single plant’ species which start to appear after the second line of dunes.
Coastal species can be a few kilometres from the sea but there are several that grow either at the high tide mark, within sight or sound of the sea or in coastal dunes. Apart from the ones already mentioned above, the following are some others that can potentially be found within sight and sound of the sea.
- Acianthus pusillus (Mosquito Orchid)
- Arachnorchis cardiochila (Thick Lipped Spider Orchid)
- Arachnorchis fragrantissima (Scented Spider Orchid)
- Arachnorchis fuliginosa (Coastal Spider Orchid)
- Arachnorchis sp Brown Bayonets (Port Lincoln Spider Orchid)
- Bunochilus flavovirens (Coastal Banded Greenhood)
- Bunochilus littoralis (Lake Saint Clair Banded Greenhood)
- Caladenia sp Selfing Coastal Dunes (Little Dune Fingers)
- Corunastylis nigricans (Port Lincoln Midge Orchid)
- Diuris orientis (Wallflower Orchid or Bulldogs)
- Diplodium erythroconchum (Red shell Orchid)
- Glossodia major (Waxlip or Purple Cockatoo Orchid)
- Leptoceras menziesii (Hare Orchid, Rabbit Ears)
- Prasophyllum elatum (Tall Leek Orchid)
- Prasophyllum litorale (Vivid Leek Orchid)
- Prasophyllum sp Late Coastal Dunes
- Pterostylis cucullata (Leafy Greenhood)
- Pterostylis curta (Blunt Greenhood)
- Thelymitra antennifera (Rabbit Ears; Lemon Sun Orchid)
Unfortunately, where there has been settlement, it is now unusual to find these species so close to the sea.
A photograph of a yellow sun orchid is July’s winning photograph and was taken by John Badger.
It is not difficult to identify a yellow sun orchid because amongst all of the Australian Thelymitras there are only two true yellow sun orchids. These are Thelymitra antennifera and the less common and very different, smaller T. flexuosa.
T. antennifera has a distinctive column with two reddish brown appendages resembling rabbit’s ears henc the connom name of Rabbit Ears Sun Orchid. Another common name Lemon Sun Orchid refers to the faint but recognisable lemon scent produced by the flower but as to why it should ever have been singled out from the other sun orchids to be called Women’s Caps1, I cannot tell.
Prior to flowering, the leaf distinguishes this sun orchid from others. Though having a red base like some of the other sun orchid, it is thin and rounded ie filiform and terete. Further, the closed buds are dark pink with lemon yellow margins of the sepals.
It should be noted that both T. carnea and T. rubra can on rare occasions produce a pale yellow variety but they will have all the features of their respective species. Also a T antennifera hybrid, T. x macmillanii, can on occasions produce yellow flowers.
- R. Bates (2011) South Australia’s Native Orchids DVD
- David L. Jones (2006) A Complete Guide to Native Orchids of Australia
- 1The Australian Zoologist 1945 – 1951 Vol II Issued by the Royal Zoological Society of NSW http://biodiversitylibrary.org/page/39059910#page/7/mode/1up accessed 1st August 2014