The winning photograph for March 2019, was Corunasylis ciliata (syn Genoplesium ciliatum). As with so many orchids, it has undergone a few name changes. Originally Prasophyllum, then Genoplesium and currently Corunastylis
Although Genoplesium was split into two with only one species remaining in Genoplesium and the others placed into Corunastylis, this split has not been accepted by the everyone. For example, eflora of SA and PlantNET use Genoplesium whilst VicFlora uses Corunastylis.
Whilst researching C. ciliatum I came across images of Prasophyllum spp. being misidentified as Corunastylis spp. and as it was originally described in Prasophyllum it seems appropriate to examine the similarities and differences between the two genera.
In South Australia (SA), the most obvious difference would appear to be size but across the rest of the country some Prasophyllum species potentially can be similar in size to the much smaller Corunastylis, although Corunastylis species are never as large as many of the Prasophyllum species.
Some of the shared features of the two genera are
- multi-flowered on a single stem
- single tubular leaf
- flowers non-resupinate, that is the labellum is above the column and the dorsal sepal is below (the only other non-resupinate flowered orchids in SA are Gastrodia, Caleana, including Paracaleana, and Cryptostylis subulata)
- Grow as scattered individuals
|Size||Tends to be a larger plant (up to 150cm), but can sometimes be as small as Corunastylis||Always a small plant (maximum no more than 90mm)|
|Leaf||Leaf sheaf opens well below the inflorescence (flower head)||Leaf sheaf opens at the base of the inflorescence.|
|Leaf||Often withered at flowering||Not withered at flowering|
|Usually curved backwards (recurved) resulting in an upright appearance of the flower.||Not recurved resulting in a more drooping appearance of the flower|
|Season||Mainly spring flowering||Mainly autumn flowering|
Jones DL A Complete Guide to Native Orchids of Australia including the Island Territories 2006
Prasophyllum and Corunastylis descriptions from VicFlora, accessed 1 May 2029
Bates R & Weber J Orchids of South Australia 1990
Jones DL, et al, Australian Orchid Genera CD-ROM 2008 CSIRO
Thank you to Greg Steenbeeke for reviewing the article.
Rudie Kuiter’s Short Paper 2 Taxonomic Status of the Mauve Leek-orchid Prasophyllum suttonii Rogers & Rees, 1912 (Orchidaceae) published in May 2017 documents how he used original source material to determine the identification of a species that was considered extinct. Prasophyllum suttonii belongs to the Prasophyllum odoratum/diversiflorum complex and is very similar to the later named Prasophyllum alpestre. It was considered to be extinct but Rudie’s view was not that it was extinct but that it had been “lost in taxonomy, and its status need to be restored”. His article documents how he used original material to help determine identification of the species he had photographed.
In his summary Rudie has some good advice about how to effectively use the material available –
- Use original descriptions and illustrations
- Original descriptions are preferred over type specimens
- later descriptions may be based upon second hand information which may or may not be accurate.
- Drawings have some value but depend
- upon the skill of the artist to show the crucial details
- upon whether they were drawings from fresh or preserved specimens
- A good photograph will be better than a drawing
- Type material is useful but may deteriorate over time
The Native Orchid Society of SA has been involved with the Threatened Orchid Project which is attempting to propagate some of our most threatened orchids. There has been some success such as Thelymitra epicaptoides (Metallic Sun Orchids) but others are proving elusive. Marc Freestone, from the Orchid Conservation Project, Royal Botanic Gardens Victoria, is a PhD student who is researching one such difficult to grow orchid genus, the Prasophyllum.
To assist with his research Marc has the sent the following request.
CAN ANYONE GROW LEEK ORCHIDS?
South Australia has about 40 species and Victoria about 74 species of the native Leek Orchids, Prasophyllum. Some are on the brink of extinction.
A major problem hampering efforts to prevent our Leek Orchids from going extinct is that they have proven next to impossible to grow in cultivation. They have proved extremely difficult, usually not germinating at all, or germinating but then dying soon after. Occasionally some success has been had (particularly with symbiotic germination) but successful germination trials to our knowledge have so far proved un-repeatable. Working out how to grow Prasophyllum is critical for the survival of many species at risk of extinction across southern Australia.
To try and change this, I will be studying Prasophyllum and their relationships with symbiotic mycorrhizal fungi.
But I need your help!
I am wanting to hear from as many people as possible who
- have tried (either successfully or unsuccessfully) to grow Leek Orchids or the closely related Midge Orchids (Corunastylis).
- have observed Leek Orchids (or Midge Orchids) recruiting from seed in the wild.
If you can help, or know of anyone who might be worth talking to, please contact me at: email@example.com or 0428 304 299.
(Funding and support for this project: Australian National University, Federal Government National Environmental Science Programme, Royal Botanic Gardens Victoria, University of Tasmania).
I would encourage people to contact Marc with whatever information that you have, no matter how insignificant you may think it is. Every little bit helps including unsuccessful attempts.
His eventual aim is to be able to work out how to grow them reliably from seed in cultivation.
Orchids are attractive and abound in variety. It is the variety that often provides the challenge of identification. As a novice it can be a bit overwhelming. In the eye of the beginner, the experienced orchid hunters appear to have no difficulty with identification. Over the years they have accumulated various clues that guide them toward accurate identification.
This series aims to document the clues that orchid hunters use.
Prasophyllum and Microtis Leaves
The first in the series relates to distinguishing between Microtis and Prasophyllum leaves. When in flower it is easy to see which is which but not so when only in leaf; and as they do not always produce flowers it is helpful to be able to separate them out at leaf stage.
Both leaves are green. Both are cylindrical. Both are hollow. Both resemble onion leaves.
The differences can be found in one or two areas. Microtis leaves are always green at the base whereas Prasophyllum leaves usually but not always will have a red or purplish coloured base. To help in identification, it is necessary to examine the base by moving the leaf litter aside to see where the plant emerges from the soil.
Prasophyllum species that could have a green base are P. laxum, P. occulatans, P. sp Jip Jip, P. elatum, P. sp Sandplain, P. pallidum (although this is short and usually in bud when noticed), P. spicatum, P validum. So further observations are necessary.
Another other area of difference is that the broken leaf of a Microtis yields a mucilaginous (thick sticky) sap; the Prasophyllum leaf does not.
Within the segregate genera used by many NOSSA members, there are two other genera with similar leaves. They are Microtidium and Hydrorchis. Again they are green, cylindrical, hollow but only hollow in the lower half. The top half is solid.
It should also be noted that Microtis can form dense colonies but Prasophyllum will never form more than loose colonies.
Finally, if upon gently feeling the base of these leaves it feels solid, that will indicate that there is a bud and it will most likely flower this season.
Think of deserts and the image is that of a bleak barren landscape with little to see but this is not so. The conditions are harsh but there is a myriad, though not an abundance, of hardy fauna and flora if one but looks closely.
But concerning orchids – No orchids have been found in true deserts….. They also appear to be absent from the arid mountains of the far north-west, or at least no-one has ever found orchids there.
Orchids need moisture and so they do not grow on unstable soils such as dry sand-hills, gibber plains or the many saline areas of the far north but on the desert fringes there are micro-climates where the moisture, humidity and soil structure is just right (to quote Goldilocks) for orchids. This micro-climate is created by [s]hrubland [which] is … [an] … important dryland orchid habitat. Besides providing shade and shelter for the orchids, shrubs like the many species of wattles, Acacia and hop-bush Dodonea drop fine leaves which help to hold the soil together and slowly break down into humus rich with nutrient and water storing capability. These shrublands usually form in soils too dry or shallow for trees. Orchids of course have no need for deep soils as they are shallow rooted.
Of the five desert botanical regions, the Eastern region contains the most number of species with over a dozen species.
Orchids of the Eastern Region – this region is from the east of the Flinders Ranges to the New South Wales border and includes the Olary Spur and Lake Frome.
|Arachnorchis toxochila – Dry Land Spider Orchid or Bow Lip Spider Orchid.|
|Corunastylis tepperi – Mallee Midge Orchid|
|Diplodium robustum – Common green shell-orchid.|
|Hymenochilus pagophilus – Mountain Shell-orchid|
|Microtis eremaea – Desert onion orchid|
|Microtis frutetorum – Common woodland onion orchid.|
|Oligochaetochilus bisetus species complex, Rusty rufous-hoods|
Oligochaetochilus sp. Blue-bush Plain – Blue Bush rufous-hood (O. bisetus complex)
Oligochaetochilus sp. Outback – Outback rufous-hood (O. bisetus complex)
|Oligochaetochilus cobarensis – Little desert rufous-hood|
|Oligochaetochilus sp. Crossed Sepals – Bibliando rufous-hood. (O. hamatus complex)|
|Oligochaetochilus sp. Bimbowrie – Bimbowrie Rufoushood (O boormanii complex)|
|Oligochaetochilus linguus – Swept-back Rufoushood|
Oligochaetochilus sp. Old Boolcoomatta – Large-lip rufous-hood (O. linguus complex)
Oligochaetochilus sp. Quartz – Quartz hill rufous-hood (O. linguus complex)
|Oligochaetochilus sp. Slender desert – Slender Desert rufous-hood (O excelusus complex)|
|Undescribed not within any other Oligochaetochilus complex|
Oligochaetochilus sp. Canegrass – Desert Sand-hill Orchid.
Oligochaetochilus sp. Oratan Rock – Diminutive rufous-hood
Oligochaetochilus sp. ‘Mt Victoria Uranium Mine’ – Uranium rufous-hood
|Prasophyllum odoratum – Scented Leek-orchid|
Prasophyllum sp. Desert – Desert Leek-orchid (P. odoratum complex)
The Gairdner-Torrens region includes, besides the salt lakes it is named after, the Gawler Ranges and the southern part of the Great Victoria Desert. Though not as many species as the Eastern region, it contains some different species including a Sun Orchid.
|Arachnorchis interanea – Inland Green-comb Spider Orchid|
|Arachnorchis toxochila – Dry Land Spider Orchid or Bow Lip Spider Orchid.|
|Hymenochilus pagophilus – Mountain Shell-orchid|
|Hymenochilus pisinnus – Tiny Shell-orchid|
|Jonesiopsis capillata – Pale Wispy Spider Orchid|
|Linguella sp. Hills nana – White haired little-greenhood.|
|Microtis eremaea – Desert onion orchid|
|Oligochaetochilus ovatus – Ovate Lip Rufoushood|
|Oligochaetochilus xerophilus – Desert rufous-hood|
|Prasophyllum sp. Desert – Desert Leek-orchid (P. odoratum complex)|
|Thelymitra megcalyptra – Scented or Dryland Sun Orchid|
Third of this group is the Nullabor region. Consisting of flat treeless limestone plains, this area, surprisingly, has two species both of which have been found close to the coast.
|Urochilus sanguineus – Maroon banded greenhood|
|Corunastylis sp. Intermediate – Halbury Midge Orchid (C. rufa complex)|
The final two regions Lake Eyre and North-Western contain the vast expanses of desert of the far north of South Australia. Definitely not a place to find orchids yet one specimen has been collected from each of these two regions.
Oligochaetochilus sp. Everard Range (L. Scott 173), Mimili Orchid (possibly O. woollsii complex) from North-Western Region.
Oligochaetochilus sp. Gammon Range (O excelusus complex) from the Lake Eyre region.
It is unusual to find orchids in the desert because they only grow when there have been good winter rains which isn’t very often. But nevertheless, here in South Australia we have over 20 possible species – an astonishingly high number for such a harsh area!
Bates R J ed, South Australia’s Native Orchids, 2011 Native Orchid Society of South Australia
Map adapted from Flora of South Australia, Fourth Edition, 1986
Charles Stanford Sutton (1895 – 1950)
A Melbourne general medical practitioner and expert on subalpine flora.
Pterostylis suttonii Name not found in the Australian Plant Name Index or International Plant Index
Prasophyllum suttonii or Mauve Leek Orchid
With a theme of Orchids and Insects for the November meeting it was hoped that there would be some entries with pollinators and therefore there would be two categories Insect Visitors and Pollinators. This month’s article will feature the Pollinator section and Insect Visitors in the next month.
In all there were four potential pollinator photographs. The insects were either scrounging around at the base of the column or else they had the pollinia attached to them. Unfortunately only one was a true pollinator so the category became Insects with Pollinia. The winning photograph of Arachnorchis brumalis with an unidentified hoverfly was taken by Chris Davey. Interestingly the other two pictures also featured Arachnorchis species with the hover fly Simosyrphus grandicornis. Resembling a wasp but minus the sting, this species is one of the common hover flies native to Australia.
Called Hover Flies owing to their ability to hover motionless in one spot, they are also known as Flower Flies because they are often found hovering around as well as pollinating flowers. It is not surprising, therefore, to find them around orchids. Yet instead of being called pollinators they are non-pollinators (Bates & Weber 1990). They visit the orchids, forage inside the flower and may even manage to collect some pollinia₁ but that is all. They may not necessarily visit another flower of the same species but if they do, they will fail to deliver the pollinia to the stigma2.
Rudie Kuiter agrees with Bates that hover flies are not orchid pollinators but just when we think we have worked it out he adds “but we have at least one orchid in Victoria that is pollinated by hoverflies and witnessed now several times and this is Caladenia catenata” (synonym Petalochilus catenatus). Notwithstanding the case for this species, it would appear that in most cases hoverflies remove pollinia so that it is not available to a more specific pollinator.
Why then are the hover flies attracted to the orchids? Is it for food? An internet image search revealed that hover flies visit the flowers of many different genera including Thelymitra and Diuris. This is interesting because flowers are the food source for hover flies but though many orchids promise food, many species do not produce the nectar and pollen (as a food source) that they desire. Diuris and Thelymitra belong to this group of non-nectar producing flower. Other orchids that don’t produce nectar include Gastrodia, Dipodium and the Duck orchids. Again, there are orchids such as Crytostylis which produce minimal nectar and with Prasophyllum the nectar is hidden in cells that require puncturing – not a good food source!
Having discussed hover flies as non-pollinators, in this month’s competition, which photograph had a pollinator? – It came last and was Robert Lawrence’s photograph of a native bee on a Dipodium pardalinum, another non-nectar producing orchid. The story of this photograph was featured in Photographing Orchid Pollinators, April 2014 Journal as well as in a previous blog on Photographing Pollinators.
Smith James, Information Centre, South Australian Museum, personal communications
Kuiter Rudie personal communications
Bates and Weber, Orchids of South Australia, 1990
Australian Museum, http://australianmuseum.net.au/Hover-flies Accessed 4th December 2014
Brown, et al, Field Guide to the Orchids of Western Australia, 2013
Jones, Native Orchids of Australia Including the Island Territories, 2006
Bates, South Australia’s Native Orchids 2011 DVD-ROM
Martin, The Vocabulary of Orchids: An Amateur’s Perspective, 2005
1Pollinia is basically a coherent compact mass of pollen that allows the pollen to be transported as a single unit
2The stigma is a sticky depression (or swelling) at the front of the column, the receiving surface for the pollinia that is necessary for germination.