Orchids come in ‘under par’ at Grange Golf course

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.

Typical of the rufus hood this Oligochaetochilus arenicola shows the sencesing leaves, pendent petals and hairs on the labellum. Photographer: H Lawrence
Typical of the rufushoods, this Oligochaetochilus arenicola shows the sencesing leaves, pendent petals and hairs on the labellum.
Photographer: H Lawrence

Below is a media release from the Natural Resources, Adelaide and Mt Lofty Ranges

Orchids come in ‘under par’ at Grange Golf course

News release
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.

For a free colourful field guide to local orchids, go to http://www.naturalresources.sa.gov.au/adelaidemtloftyranges/home and search for ‘orchid’.

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2011 POST FIRE SURVEY – MESSENT CONSERVATION PARK

Cathy Houston

Conducted by the Conservation group of the Native Orchid Society of South Australia Inc. for the Department of Environment and Natural Resources.

Members of the Native Orchid Society of South Australia and two volunteers conducted a three day orchid survey of Messent Conservation Park, following a prescribed burn that took place in March/April 2011.

The survey in burnt areas was undertaken from Friday 9th – Sunday 11th September, inclusive. A maximum of eleven people took part, not all being present for the entire survey time. Participants worked in pairs (or threes if numbers dictated such) and conducted ramble surveys within very rough grid areas of about 500 meters square. Because of the size of the burn area and access difficulty, none of the internal area was surveyed. However, many habitats were covered and extrapolation could predict what would be likely to occur in these areas. Some other vegetated areas were visited as well. These included flats covered in rushes, or sedges and rushes, a 16 month old prescribed burn area, a Pink gum (Eucalyptus fasciculosa) rise, mallee woodland and a Banksia herb-land.

Observations were taken of species present, numbers and any other detail of note, together with GPS location. A numbering code was used for most species.

The results were somewhat variable, presumably dependent on habitat types and their orchid population prior to the burn, the temperature of the burn and to a lesser extent, the emergence or otherwise of orchids prior to the time of burning. For instance, only one small population of Corunastylis (Genoplesium) was noted, this being a species that would have been flowering at the time of the burn. Similarly, no Eriochilus were observed in the survey area. However, Leporella fimbriata which emerges at a very similar time was present in some very large colonies.

The most abundant orchid by far was Pyrorchis nigricans. It was encountered in nearly all habitats of the survey area, the only exception being limestone ridges where it rarely appeared. Flowering had been promoted by the burn with perhaps about half the population in flower/going to flower. Density of the population fluctuated but it seemed to be consistently present. However, its absence was noteworthy from an area of burn undertaken in May 2010. The habitat was ideal for the species and given the proliferation throughout the 2011 burn one would have to speculate about the timing of that burn on that (and perhaps other) species. Very few species were located in that area at all. It has to be said in fairness though that the only Thelymitra epipactoides found in any burn area was seen in this 16 month old burn.

Perhaps the most orchid-rich habitat with regard to number of species was the limestone ridges. Some of the open flats had the least diversity. It was not easy to ascertain what the dominant vegetation had been in these areas. Conversely some of the flats had a good scattering of orchid species, the numbers of each being relatively low.

Winter flowering species were conspicuous by their low representation.  No Bunochilus (Pterostylis) were seen, few Urochilus (P.) sanguineus, Diplodium (P.) dolichochilum, Acianthus pusillus, Corysanthes (Corybas) species and Cyrtostylis robusta were seen in the burn area.  The only exception was Linguella (Pterostylis) sp. Mallee. It was encountered in small to medium sized colonies throughout the area, usually with a reasonable number of capsules developing. In a vegetated location Diplodium species was seen in good numbers.

Threats to orchids were minimal. Rabbits were present in noticeable numbers along the northern boundary. Similarly, there was some weed incursion along the northern boundary, Capeweed and one other being the main ones seen. Some predation was observed within the burn area, but nothing we would consider notable. Rabbit activity was also very evident in a flat/Pink gum rise on the track leading south to the boundary. Deer prints were observed throughout the areas we covered. A small flock of sheep encountered in the north eastern sector is of concern. They had free access to the park via a “kangaroo door” under the boundary fence, something they negotiated with ease when disturbed by a vehicle.

Species of significance were Thelymitra matthewsii and T. epipactoides, these both being nationally threatened species. Historical records existed for T. matthewsii from this park, but it had not been observed for decades, despite intensive searches having occurred following the 2002 burn. Some of this surveys records bear a similarity to historical records but since the latter were recorded prior to accurate global positioning systems it is uncertain about the actual locations. This species was encountered as mainly individual plants in about six different locations, usually in very low numbers. Some plants were just leaf but others were seed capsules. All but one group were located in burn areas, the species being very difficult to observe without the removal of much vegetation. It was noted that some of the area where the species was seen had been slashed. It was felt this could be beneficial to them. Observations in the lower South East seem to reflect this type of disturbance is beneficial to T. matthewsii and Thelymitra in general.

More than 60 plants of T. epipactoides were located in one area of a few hundred meters squared, with the exception of the aforementioned one plant in the 16 month old burn. Despite searching of hectares of similar sedge/rush-land, no others were located. Here again, it was thought that some random slashing of this habitat may benefit orchids that like the open areas, viz. Thelymitra, Diuris sp. Short tailed, Glossodia major, and some Caladenia species.
Present in low numbers on the limestone ridges was Arachnorchis (Caladenia) tensa, another nationally threatened species. Despite its national rating this species is more prolific in South Australia.

Another orchid that appeared in considerable numbers and most habitats was Arachnorchis (Caladenia) sp. South East. It grew as single or few plants right up to sizeable collections of plants, sometimes with up to about 50 in a group. Diuris sp. Short tailed was widespread and moderately common. Glossodia major was encountered as mainly single plants widely scattered. Caladenia carnea was in very high numbers under fairly dense mallee on the northern boundary. Microtis species when it was encountered, was in colonies with high numbers of plants. As a generalisation, Thelymitra were absent or in very low numbers. Exceptions to this were T. antennifera and T. benthamiana which were usually seen in very low numbers but widespread throughout the burn area. It was interesting to note that few of the latter were likely to flower, which contrasts with the 2002 burn when flowering was prolific.

One species promoted to flower by the burn was Prasophyllum elatum. It was widespread in most habitats, but not often in the flats. Plants varied tremendously in size and stature with some quite small plants flowering/going to flower. Predation of the leaves was relatively high, with nearly all being chewed down to between 100 to 150 mm. Buds were emerging from the open top of the leaf, instead of emerging from the side of an intact leaf. There were other Prasophyllum species present, but the survey was just too early to identify what these are likely to be. Most of these were found on the limestone ridges.

The orchid list held by NOSSA for Messent Conservation Park prior to this survey must have been somewhat limited because the number of species on our list has now been doubled. With the rediscovery of T. matthewsii in several locations within the park, the other two nationally threatened species present and the expanded knowledge of orchids within the Park we must consider this was a very successful survey. We thank DENR South East for making this survey possible.

An Eriochilus study in the Southern Flinders Ranges: 2010

R. Bates

Until  2009 when NOSSA did an orchid study of Wirrabara Forest Reserve the parsons bands or Eriochilus were thought to be rare in the Flinders Ranges, but that year Eriochilus were found all the way north to Mount Remarkable and were often seen as locally common.

In 2010 I did two visits, one in April and one in May to see how well they flowered after a wet spring the previous year.

Results: all colonies at Wirrabara flowered spectacularly in April 2010 but at Mt Remarkable flowering was poor.  No leaves were visible at the time.  The flowers were white with some strong colour and stems were quite bristly, see image. At Wirrabara plants were sturdy with up to four flowers per scape yet at Mt Remarkable plants were spindly and flowers mostly single.

It was thought that the reason for this difference lay in the wet spring of 2009 at Wirrabara with much less rain at Mt Remarkable.

The second visit in May showed a different picture. Very little rain had fallen at Wirrabara in autumn and the stems of all plants had hardly elongated.  Yet seed capsules were plentiful.  In contrast, Melrose near Mt Remarkable had received good autumn rain and stems there had doubled in length.

So it seems that the number of flowers and strength of plants depends on rain the previous season whilst height of stems depend on rain during the current flowering season.

Curiously, in both areas a second flush of flowering occurred in May with the second flush at Wirrabara producing tiny flowers on short spindly stems (see image) while those at Mt Remarkable had larger flowers on tall stems.

Flowers seen in both areas were similar in appearance and both had leaves which were large, apiculate, dark green, ribbed and hairy above, purple below.  Both the April flowered and May flowered plants belonged to the same taxon and clearly flower size and number, and scape length, are not useful in separating species as they are so variable.

On the other hand leaf shape, texture, ribbing and colour below are important in identifying the species as these are constant features.

Conclusions: only one species of Eriochilus occurs in the Flinders Ranges and this is the same as the common woodland species in the Mt Lofty Ranges.  This species has never been named officially but is generally known as Eriochilus sp Hills woodland and is best identified by it’s leaf … see image.

This is the most common of three or four Eriochilus species in SA.

Leaf of April flowering Eriochilus at Wirrabara dwarfing later May flowered
plants behind it.

Eriochilus species Hills near Mt Remarkable in May 2010

Surveying in the South East

Cathy Houston

In recent years a number of N.O.S.S.A. members interested in field work have been involved in surveys for orchids. These include surveys for individuals as well as government or semi-government organisations.

Late in March this year we undertook an Autumn survey of a forest in the South-East known as The Marshes.  As the name suggests the area is well served with swamps as well as forest of Stringybark with sandy soil.  Several members met the day before to check some areas in the upper SE.  Here in sandy-heath there were two species of Corunastylis in flower, often not very distant from each other, but each favouring different habitats.  In the heath were C. aff. rufa in flower and capsule.  In mallee open forest C. tepperi had recently commenced flowering.

In areas dominated by granite outcrops were found Eriochilus cucullatus flowering and perhaps another un-described Eriochilus species.  Leaves were not present, so no distinction could be made from flowers alone.  However, in mallee the flowers were larger and supported on much taller stems.  Those on the granite were small flowered on short stem, there being no apparent difference in the flowers themselves.  Here also the C. aff. rufa was seen in flower and capsule.

In the lower SE a sojourn into Honans Native Forest Reserve produced yet different species, some in flower.  C. ciliata was already in capsule, the distinctive greenish-yellow lateral sepals still evident and under magnification hairs could be detected on the labellum.  C. despectans had the very last flowers on the top of the scape as well as capsules on earlier flowering specimens.  Speculantha obesa had just commenced flowering.  In most cases the inward facing, smallish flowers had only the bottom one open with buds on the stem above.  Rosettes were not yet present. We were amazed to find Pterostylis nutans rosettes already emerging.  A little less surprising was Leporella fimbriata, but the number of flowers seen at this early stage was few.

The Marshes is not renowned for being prolific in Autumn flowering orchids but our visit was scheduled to try to locate as many as we could.  By the second day we were rewarded with the discovery of plenty of Spiranthes alticola, which were represented in most of the swamps in the western sector.  It is interesting to note that years ago they were found prolifically in the eastern sector but this appears to have dried out too much for them these days.  S. obesa was found in very low numbers and this time one of the plants already had a capsule.

Perhaps the greatest excitement was afforded when two members thought they found Cryptostylis subulata leaves.  All the surveyors collected for lunch and soon were down at the site considering if the leaves lived up to the name.  Much discussion ensued.  If only there was a flower to confirm the diagnosis.  After what seemed like an age a “tired” flower was located!  C. despectans had previously been recorded for the forest and a considerable amount of time was spent in searching known locations but to no avail.  Not Autumn flowering but the other orchid found was Dipodium roseum which was heavy with capsule.  Some of the stems had up to eight large pods hanging on them.

At Mt. Lyon Native Forest Reserve we were able to view many Cryptostylis subulata in flower and capsule.  Another trip was made to Honans to locate C. subulata from provided GPS readings.  After a bit of interesting navigation both swamps were located.  However we were unable to find the target species, one swamp appearing to now be too dry to sustain this species.

A quick trip was made to Telford Scrub Conservation Park following one of the survey days.  Here we saw Eriochilus sp. in flower.  This time they were large flowers with tall, almost robust stems.  Leaves were yet to emerge.  Another surprise was to await us here.  Bunochilus spikes were well up and it was evident there were two species represented.  Some of the spikes were quite pinkish with leaves still tightly furled on the spike.  Flowering will clarify more for us; some of the spikes will have a long growing time.

Upon completion of the surveys some members headed for Piccaninnie Ponds Conservation Park in yet another attempt to locate Eriochilus in flower.  This time we were successful.  It is a long way to travel when not knowing the exact flowering time for the area, and those times can change with each season!  On short thin stems, small flowers with still the same general appearance were what greeted us.  There were buds and capsules present as well, but most interesting to us was the presence of obviously earlier capsules.  One had already dehisced and all were far more robust and distinctly different from the smaller red-striped hairy capsules of the currently flowering species.

On next to more Native Forest Reserves.  Once again the target species was Eriochilus but we were hoping to find among the flowers some colourful pink specimens.  It seemed this time we were a little too early because few flowers were seen.  However, a strong coloured pink flower was located and so became much photographed.  The next area was low open forest with bracken and heath understorey.  Showers caught up with us and lowered the visibility very considerably.  This made it hard to look for small greenhood type flowers but possible to find, once again Eriochilus sp.  Some lovely double headed flowers were seen but no leaves were evident.

At this early stage of the year it was amazing how many orchids were seen, albeit over quite a wide ranging area.  Perhaps some worthwhile early rains in the lower SE had been useful, but most of the species are not heavily dependent upon this for their Autumn appearance.