Conservation of orchids takes many forms, one of which is weeding. NOSSA members often assist the Threaten Plant Action Group in this area. There are several sites where significant orchids are under threat from invasive weeds; and over the years, through consistent weeding, the weed front has been pushed back allowing the orchids an opportunity to recover and even increase in numbers. It is an ongoing task but seeing the orchids recover makes it an encouraging task BUT …
This activity is heavily reliant upon volunteers. And those who regularly volunteer deserve a big thank you from the community. BUT ….
More helpers are always needed. If you are interested in seeing the orchids, consider joining one of the weeding activities that are held throughout the year (these are advertised on this website). Often the weeding activities target a specific weed, so it is great for a beginner who does not have an in-depth knowledge of plants.
With the development of cities here in Australia, many of our orchids were lost as habitat was cleared and the newly arrived settlers built houses and reconstructed the gardens they knew from the Old World; but the odd pocket of native bushland has survived. Cemeteries and golf courses have often been the only refuge for remnant bushland. One such refuge has been The Pinery, Grange Golf Club, the only known location of Oligochaetochilus arenicola (syn. Pterostylis arenicola) on the Adelaide Plains. In the National Parks and Wildlife Act, this orchid is scheduled as vulnerable. The Golf Club left this site intact and has been supportive of the conservation efforts of the Threatened Plant Action Group who in turn have received assistance from the Native Orchid Society of SA and the Natural Resources Adelaide and Mt Lofty Ranges.
Below is a media release from the Natural Resources, Adelaide and Mt Lofty Ranges
Orchids come in ‘under par’ at Grange Golf course
30 September 2015
A tiny remnant population of rare orchids which survives in a patch of bush on Grange Golf Course has increased 50% since last year, according to a new survey.
The survey conducted this month found 1200 individuals of the Sandhill Greenhood Orchid (Pterostyllis arenicola), a nationally threatened species which is considered critically endangered in the Adelaide and Mt Lofty Ranges region.
When surveys began 20 years ago, only about 100 plants survived at this site. But the latest survey has revealed the population is steadily increasing
The orchid comeback is thanks to decades of care by four groups involved with the annual survey: the Threatened Plant Action Group, the Native Orchid Society of SA, Natural Resources Adelaide and Mt Lofty Ranges, and with support from the Grange Golf Club.
The tiny fragment of native pine bushland in the middle of Grange Golf Course is one of the only known locations of this species within the entire Adelaide and Mt Lofty Ranges region, with other small populations known from near Wellington and Tailem Bend.
The orchid grows 10cm-25 cm high and produces hood-shaped flowers that are green and brown or red-brown with white markings. Most species of orchid flower for only a short period and for the Sandhill Greenhood, it will flower only for the next few weeks.
Grange Golf Course just happens to provide ideal conditions for the plant: red sandy soils and an over-story of native cypress pine trees.
Dedicated project partners have tackled the main threat to orchids – suffocation by Perennial Veldt Grass and Soursob weeds – through years of patient hand weeding.
The orchid comeback is a great success story of collaboration across the community to save one of our state’s tiny floral gems.
As a demonstration of nature’s interdependence, conserving the Sandhill Greenhood also means conserving a particular mycorrhizal fungus that must be in the soil for Sandhill Greenhood seeds to germinate. In addition, the flowers must be pollinated by a particular type of insect, the fungus gnat. The gnat is attracted by the orchid’s pheromones and tries to mate with the flower, only to find itself loaded up with a packet of pollen which it then transfers to the next flower as it continues its romantic adventures.
While the survey results are good news, the Sandhill Greenhood population is still precariously small, and it is hoped that as the population grows, so do the options to secure the species into the future.
South Australia has over 260 species of orchids, including 50 species of greenhood.
This week’s post is taking a brief look at a paper by Noushka Reiter, Mark Clements and Kate Vlcek which appeared in Muelleria, Volume 31: 69 – 76, 2013.
Titled “An examination of Pterostylis xerophila (Orchidaceae) and the confirmation of P. lingua as a new species in Victoria” this paper seeks to ascertain whether the records collected are correctly identified, that there are differences between them both in morphology and associated vegetation.
Both P. xerophila and P. lingua are found in South Australia where they are known, respectively, by the synonyms Oligochaetochilus xerophilus and O. linguus. In fact the type specimen for O. xerophilus is from South Australia.
In the introduction, the authors give a detailed description of Oligochaetochilus otherwise known as the ‘rufa group’ which differs from Pterostylis, in the strict sense, in several features. Some of the main features of this group are:
Basal rosette of overlapping stemless leaves
Leaves senesced, withered and died, by flowering
basal half joined
tips become long and threadlike
is very mobile
has obvious long white hairs and often short hairs as well
Later in the articles, the differences between the two species are discussed. There is much of interest concerning the two species but one outcome of the research was to establish that P. lingua (O. linguus) had been incorrectly identified in the records and by correcting the names of the specimens the authors were able to confirm that it did occur in Victoria.
To find the answer to the authors other questions, read the paper
And for those that need a glossary of the terminology used, click here
For images of P. xerophila (O. xerophilus) click here