Last year we waited for the rain. The rain heralds the start of the orchid season. Last year the season was dry, very dry. It was below average and it was hot.
So how did the orchids fare in the Adelaide Hills? The start of the season was slow with our first field trip not being until May 26 because of the lack of rain.
At the time, the smallness of the plants was noticeable with one specimen of flowering Leporella fimbriata standing no more than 2 cms. Normally the flower stem can be up to 25 cms tall. This trend of smaller plants continued throughout the year.
The following two photographs show the difference in size.
And on January 28, we came across the smallest flowering Dipodium pardalinum that we’d ever seen. Normally, this genus can grow up to about 100 cms in height but this one barely reached above the height of Robert’s shoe, ie, about 10 cms. True this was an exception but overall there not many plants, and even they were spindly and small in comparisons with previous years.
Below are two photographs illustrating the size difference
So what is the outlook for orchids for 2019? That will depend upon the rains.
When does the orchid season get going? Again that depends upon the rain but expect to see the autumn orchids about six to eight weeks after a good rain episode.
Anzybas unguiculatas (common name Little Pelican or Cherry Helmet Orchid) was the main focus for this month’s competition with three photographs of this diminutive flower.
The other photographs were Ed Lowrey’s close-up of a triggered Urochilus sanguineus labellum, John Badger’s first Diuris palustris sighting for this year and Pauline Meyer’s mass flowering of Leptoceras menziesii post fire. Of the Anzybas, Jenny Pauley entered two and Lorraine Badger one. Jenny Pauley’s photograph of two flowers was the outstanding winner.
Originally named Corysanthes unguiculata (1810), then Corybas unguiculatus (1871), the genus name was changed in 2002 to Anzybas in recognition of its distribution both in Australia in New Zealand. Since 1945 it had been recognised that the New Zealand species Corybas cheesemanii was a synonym for Corybas unguiculatas although the juvenile plant can have two leaves unlike the Australian species which is single leafed.
An interesting feature of this flower is the prominent white ears at the rear of the helmet (not clearly seen in this photograph) which are part of the labellum.
An unusual aspect of this photograph is that the colour of the underside of one of the leaves. It lacks the characteristic distinguishing feature of the purple underside of the leaves. According to orchid growers, the light affects the leaf colour. Heavy shade produces green leaves. It is possible that the heavy leaf litter where this plant was growing provided enough deep shade to cause the colour loss.
Bates (1990) states that it (has) not proved amenable to cultivation, but it has, on rare occasions, been benched at NOSSA meetings with the most recent occurrence was in July 2010 but it remains a very difficult plant to cultivate. The electronic version Vol 34 No 7 has a photograph of the plant just visible within the moss.
It is not always easy to photograph this species as not only is it rare with limited numbers but there are very few sites where it can be found. Added to that is that the window of opportunity is short in South Australia with a flowering time from June to August compared with those interstate which can range from May to October.
There has always been an interest in Australian orchids. Over the years there have been many photographs of orchids. This stereographic postcard from 1928 is a study in beauty –
This postcard is held by the State Library of Victoria.
Although the distribution covers the Southern Lofty, Kangaroo Island and the South East regions of South Australia, it has become increasingly rare due to loss of habitat which consists of leaf litter on damp soils. As a result, there are very limited localities where they can now be found.
It is one of our earliest helmets to flower which is from June to July.
For the last couple of years, NOSSA has been conducting spring tours at the Mt Lofty Botanic Gardens, South Australia, showcasing our beautiful native orchids to visitors far and wide. They have come from not only Adelaide but from interstate as well as overseas from such countries as America, Germany, England and many others. If you are planning to be in Adelaide during spring, then consider joining one of our walks, but for those who cannot attend here is a video for you. So watch and enjoy …….
The title of this article refers of course to mallee midge orchids of the genus Corunastylis which have been poorly understood.
Summer and autumn 2011 saw good rains across the Murray Mallee from Pinnaroo to Renmark and thus NOSSA members took the opportunity to study mallee midge orchids in flower in March and April. The results are summarised here.
To match species to habitat.
To assess the distribution and population of each species.
To take images of all species.
Midges were found all the way up to Chowilla sand hills, which are just north of the River Murray. Almost every patch of mallee eucalypts seemed to have some Corunastylis species but an understanding of their ecology was needed to find the flowers. Degraded or weedy mallee did not have any midge orchids, nor was hard clay, loose white sand, bare trampled soil or dense ground cover worth searching as midges are very small plants and easily crushed, covered up or sand blasted.
Flowering plants were found mostly in the leaf litter under mature mallee, often with associated patches of native pine or circles of Triodia sp. (porcupine grass). Areas with extra water run off and disturbed soil along road corridors seemed to have produced localised population explosions. A 4WD vehicle proved handy for reaching remote corners of larger parks like Billiat Conservation Park near Alawoona.
The most common species was the red and green flowered mallee midge Corunastylistepperi while the similar but purplish Corunastylis sp. Intermediate came in second. Next came the black midge orchid C. nigricans which seemed to have finished in early March and were found mostly in capsule.
Species of the Corunastylisrufa complex were mostly found in the southern fringes of the mallee. Their classification is ambiguous seeing Australian orchid expert D.L. Jones says Corunastylis rufa is confined to NSW. The un-named species of the complex seen included Corunastylis sp. Dark midge and Corunastylis sp. Narrow segments.
In any case, no fringed labellum species of any kind were observed, so all mallee midges belong to the C. nigricans and C. rufa complexes.
Tiny fruit flies of several species were seen working the flowers but we could not tell if each midge orchid attracted a different fly as the flies are too small to compare! I suspected that specificity of pollinators is low as apparent hybrid midge orchids were noted.
Recognising the different mallee midge orchids:
If the flowers are bright green and the labellum is rounded, deep purple or maroon then it will be C. tepperi, also known as C. fuscoviride. The latter is a better name as it means bright dark and green. C. tepperi has a narrow spike of many tiny flowers. The finished flowers and capsules will take on a yellowish look.
If the labellum is rounded and the flowers are mottled brown to wholly purple-brown, except for white or white striped petals, the species is C. sp. Intermediate.
DNA studies may be required to check the species limits of the many taxa found.
It is doubtful that such a good display will be found next autumn!
Many thanks to NOSSA members who sent me images of mallee midges recently, especially June Niejalke.
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