Tag: Pterostylis

Do we meet or not meet? -Basal Flanges in Subgenera Bunochilus

The following article by Rosalie Lawrence appeared in the electronic version of the Native Orchid Society of South Australia Journal, Vol 47 #6 July 2023. For the purpose of this article, the segregate genera Bunochilus was used to narrow it down and differentiate it from the rest of the Pterostylis genus. This article includes additional information not in the Journal article

Recently Robert & I visited Diamond Creek, Victoria where we photographed a Bunochilus which we thought looked remarkably similar to our hills B viriosus. Anyway it was subsequently identified on iNaturalist as B smaragdynus. In the iNats comments, the Victorians often mentioned the meeting together of the broad basal flanges within the flower as an identifying feature.

So on our recent NOSSA trip to Hardy’s Scrub, Robert made it a point to photograph the basal flanges of the Bunochilus. I too did the same. Lo and behold, we had flowers with the flanges touching and others where it did not! So did we have two species of Bunochilus at Hardy’s Scrub?

Well when we get home we read June’s descriptions for the two species and note that she has underlined the touching of the basal flanges for B smaragdynus but mentions in the description of  B viriosus that they can also touch. Puzzlement! Solution – give June a call! It’s always great chatting with June because it is hard to get everything into one small volume and with talking a better picture emerges.

After talking to June, keeping in mind what we discussed, I then spent time on iNaturalist viewing all 285 observations of B smaragdynus and 115 B viriosus observations but I soon noticed from the Victorian commentators that I also needed to look at the 41 B chlorogramma and some of the B melagramma observations (1,619 was way too many to go through!).  I also viewed Vicflora pages on the description of their three species.

Basal flanges of Bunochilus viriosus not touching

Photographer Robert Lawrence



The following is what I noticed

  • The Victorians were often using the flanges as an identifying feature for identifying B melagramma
  • There was great difficulty in separating out B chlorogramma from B smaragdynus. To quote one Victorian –  ‘It is notoriously difficult to tell the difference between P smaragdya  & P chlorogramma’
  • B melagramma has small basal flanges (appear parallel) and never touch but the other three species have well developed basal flanges (triangular shaped) and may or may not touch (see Vicflora’s descriptions).
  • Published descriptions of the species occurred

~ Pterostylis smaragdyna 1993

~ B chlorogramma 2002

~ B melagramma 2002

~ B viriosus 2006

But it was the differences between B smaragdynus and B viriosus that I needed to look up and particularly whether the flanges were of significance or not. Also, June has always stressed that features are not hard and fast, so I needed to keep that in mind as I made my comparison.

My general observations of the observations of B smaragdynus and B. viriosus are~

  • B smaragdynus
    • Although most flowers opened at once, there was still a large proportion that didn’t
    • Flowers mainly a few and tended to be top heavy
    • There were some pollinated flowers
    • Along the way, I noticed the growth habitat (when I could see the background), was at the most one or two, or to quote Gary Backhouse – “small, sparse colonies”
    • Basal flanges did not always touch but were always a wedge shape
  • B viriosus
    • Most flowers opened consecutively but there were some where all the flowers opened at once.
    • Mainly lots of flowers on an inflorescence but there was a reasonable amount with just one or two flowers.
    • Growth habit, probably the most notable difference, colonies consisted of several flowering plants (sparse would not be the word to apply!)
    • Did not see any pollinated flowers
    • Rare to find an image of the flanges, but they were variable concerning touching yet always wedge shape

Basal flanges of Bunochilus viriosus touching

Photographer Rosalie Lawrence

Conclusion

There doesn’t appear to be a reason to include observing the flanges as there is no difference between these two species. But when there is a possibility of B melagramma being present such as in the South East and on Kangaroo Island, then it becomes necessary to include looking at the flanges when making an observation.

A surprise was to notice that the growth habit is significant point of difference between B viriosus and B smaragdynus as I was mainly looking at the flanges. Of course, there are some other features to be considered but that is for another time.

A curiosity, whilst researching this article I discovered that Diamond Creek is the type location for B smaragdynus

For images of basal flanges see page 202 of June’s book.

Monthly Terrestrial Orchid Culture – June

It’s June and the the orchids tubers are on the move. And yes there are some tasks for this month but as can be seen by Les Nesbitt’s notes in the June 2019 NOSSA Journal (Volume 43 N0 5) there is not a lot to do.

Diplodium robustum  (syn Pterostylis robusta) – one of the cauline greenhoods


June is cold, often with frosty mornings and sunny days. Terrestrials can take -20C but any colder results in permanent damage. If you live in the country, you may need a solid roof for frost protection. Frosts are rare these days in Adelaide. I have black rubbish bins full of water under the benching in my glasshouse to moderate the temperature. The bins absorb heat in the daytime and radiate it out at night. If it is not frosty it will be cold wet and cloudy. Growth will be slow and there are few flowers out. There is not a lot to do in the terrestrial house.

Pterostylis robusta and Acianthus pusillus flower this month. If there are no flowers this year, they probably aborted due to high temperatures or excessive dryness over summer/autumn. Try putting the pots under the bench in a cooler position next summer.

The last of the terrestrial orchid leaves should appear this month although there are always a few stragglers. Tubers that formed in the bottom of a pot have a long way to grow to reach the surface. Sometimes they come out the drainage holes. If no plants appear, do not throw the pot away. Sometimes orchids take a year off and send up a leaf the following year. They are capable of forming a new tuber from the old without making a leaf. Gather together the “empty” pots in a corner. They can be left for another year or you can knock them out next month to try to establish what can be improved. Most weeds have germinated by now so weeding gets easier.

It is hard to drag yourself away from the heater this month but at least once a week go out on a wet night with a torch and examine your orchids for slugs, snails, earwigs, cockroaches, grubs and beetles. They always feed on your best orchid buds.

The SAROC Fair is in June. Clean up your flowering pots for the NOSSA stand. Other orchid clubs hold winter shows in June & July. Go along and see if there are any interesting terrestrials on the trading table.

Clarification of Pterostylis valida

Short Paper 3 Identity of Pterostylis valida (Orchidaceae) by Rudie Kuiter was published in June 2017. In this paper, Rudie has tackled the difficult group of Rustyhoods or Oliogochaetochilus (specifically Pterostylis valida) within the genus Pterostylis. Many of the different species occur in isolated pockets over a wide geographical range. Differences can be subtle but Rudie has sought to clarify the distinction between P. valida  and similar species. Click here read the complete paper.

A typical flower at the type-locality, green with the usual stripes on the transparent parts of the hood, cup-shaped synsepalum and dark labellum swellings. Opposite page Image of the original 1941 description page by Nicholls of Pterostylis valida as a variety of P. squamata. It was cropped with the deletion of the description of Caladenia hastata, the other species. 
A typical flower at the type-locality, green with the usual stripes on the transparent parts of the hood, cup-shaped synsepalum and dark labellum swellings. (Image from Rudie Kuiter’s Short Paper)

 

Orchids In Remnant Roadside Vegetation

This week’s post written by Leo Davis is an article (slightly edited) from The South Australian Naturalist 91 (1): 34 – 37 January – June 2017. In this article, Leo highlights the importance of  the role of roadside vegetation in preserving the native orchids and flora.

All photographs are by Leo Davis.

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 OrcFig 1: Thelymitra antennifera hybrid

One of my rules of thumb is ‘If I am in a Conservation Park, I’m on ground that nobody could make a living from.’ One, usually more, of nutrient poor soils, excess salinity, extreme rockiness, steepness, poor moisture retention, low rainfall or even being waterlogged, will be a feature of the location. There are a few odd spots that have survived partly intact, that have good soil, sufficient rainfall, etc. These include cemeteries (The Nationally Critically Endangered ghost spider orchid (Caladenia (syn. Arachnorchis) intuta) holds on in a cemetery on Yorke Peninsula) or exclusion zones around water storages (including a reservoir reserve in Lobethal that the public can now access) or abandoned railway yards (including Sherlock, where so far I have found 21 species of orchids and part of a reserve in Halbury.)

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig 2: Little Yellow Club Mallee Spider Orchid Caladenia (syn Arachnorchis) verrucosa

When I go in search of plants with the Botany Group of the FNSSA (Field Naturalist Society of South Australia), or for orchids with NOSSA (Native Orchid Society of South Australia), or when I do surveys of threatened orchid species with DEWNR (Department Environment, Water and Natural Resources), or orchid seed collection with the Adelaide Botanic Gardens, or go on weeding parties to protect endangered species, the destination is always one of these deprived, rejected sites. The orchids I see are those adapted to or just hanging on in such sites. We never see orchids that lived on better soils, say on the Adelaide Plains. How many have become extinct?

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig 3: Common Mallee Shell Orchid Pterostylis dolichochila

Wherever the land was suitable for agriculture it was clear felled. Almost nothing of the original flora and little of its associated fauna, were left. But there is a tiny flimsy exception. Crossing these highly productive agricultural zones are roads and sometimes these have remnant vegetation. For a person interested in orchids, these narrow strips are normally areas of slim pickings but occasionally finds are made. Near Halbury, the Nationally Endangered Halbury rufoushood (Pterostylis sp. Halbury or Oligochaetochilus lepidus) can be found in some roadside spots.

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig 4: Mallee Bearded Greenhood Pterostylis (syn Plumatichilos) sp. Mallee Bearded Greenhood

The most remarkable piece of roadside vegetation that I have come upon was discovered by and shown to me by Glenn Dean, the Environment Officer with the City of Murray Bridge. He found a section of predominantly broombush (Melaleuca uncinata) vegetation, only about 200 m. long, on the verges of a single car sandy track, east of Murray Bridge. It is so close to the vegetation that cars can be scratched. I have found 24 species of orchid (Glenn has found more) blooming there sometime between March and October each year. All images shown here (Figs 1–11) were made at this site. If the little used road was not there the land would have been under crop, being equal in quality to regularly cropped fields to either side, and is of much higher quality than any normally allocated to Conservation Park status. Most of the orchids found can indeed be found in some of the poor sites dedicated as Conservation Parks, including species similar to those found at Ferries McDonald and Monarto Conservation Parks with their poor sandy soils. But this spot, which for some reason supports species that do not grow just 100 metres east or west along the road, has such species as the Nationally Critically Endangered Mallee Leek Orchid (Prasophyllum constrictum) (Fig. 8), that requires soils as good as those demanded by wheat, so it is essentially doomed.

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig 5: Rusty Rufoushood Pterostylis biseta (syn Oligochaetochilus bisetus)

Its single plant sighting here is regarded as a ‘rediscovery’ of a species not seen for years. In the longer term I guess this tiny site of orchid species richness is in a transitory state and most species will disappear. The surrounding cropping land is neither a source of seed nor a suitable landing site for it and it provides damaging wind blown nutrients and other chemicals. So I will cherish it while it lasts and hope others appear, if only briefly. Here is a reminder, that most of you do not need, of the value of roadside vegetation (with the understanding that it can contribute to native animal mortality) and that we should manage, extend and guard its presence.

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig. 6: Rufoushood Pterostylis (syn Oligochaetochilus) boormanii complex sp.

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig. 7: Cinnamon Donkey Orchid Diuris palustris

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig. 8: Mallee Leek Orchid Prasophyllum constrictum

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig. 9: Limestone Tiny Shell Orchid Pterostylis cycnocephala
(syn Hymenochilus calcicolus)

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig. 10: Caladenia (syn Jonesiopsis) capillata x Pheladenia deformis hybrid

Microsoft Word - SAN Vol. 91, No. 1, Jan-Jun 2017 pp. 34-37 Orc

Fig 11: Small Rustyhood Pterostylis pusilla (syn Oligochaetochilus pusillus)

Orchid Basics – Labellums and Columns

Orchids are unique in the floral world. Two distinctive characteristics that set orchids apart from other plants are the labellum and the column.

The labellum is a modified petal.  It is extremely varied in appearance; “often lobed, spurred, adorned with glands, appendages of calli (callus, a hardened swelling or thickening of the skin), sometimes mobile and highly irritable and often brightly coloured”. * The labellum is important for pollination.

The column (as described by Bates and Weber) “is a distinctive feature of all orchids and a unique structure in the plant kingdom. It is formed by fusion of the male parts ‘stamens’ and female organ ‘pistil’.”*

Below are examples of the various types of labellums and columns in some South Australian terrestrial orchids. Each genus has its own characteristic labellum and column.

Sun Orchid
Thelymitra – though the labellum is almost indistinguishable from the other petals and sepals, the column is quite complex.

Hyacinth Orchid
Dipodium or Hyacinth Orchid

Greenhood
Pterostylis or Greenhoods – generally a simple labellum with the column hidden well back into the hood.

Spider Orchid
Arachnorchis (syn Caladenia) can have quite varied and complex, mobile labellums

Helmet Orchid
Corybas or Helmet Orchid – the labellum dominates and the column is hidden deep inside the flower.

Donkey Orchid
Diuris or Donkey Orchid – the labellum is divided giving the appearance of more than one structure.

*Bates and Weber Orchids of South Australia 1990

 

Pterostylis Pollinators

Rudie Kuiter et al have been observing orchid pollinators over many seasons spending hours watching and becoming familiar with pollinator interaction with the orchid, learning when to anticipate pollination activity.

Their observations of various Pterostylis species has been documented in Overview of Pterostylis Pollination (Orchidaceae) in Victoria. In all, they observed 53 Pterostylis species and 40 species of pollinators from several different genera. They noted that some pollinators species were active most of the day but others were only active in the late afternoon whilst others were “only seen on dusk and possibly are nocturnal as well”.

Pterostylis curta (Blunt Greenhood)

 

 

Banded Greenhoods Bundled Together

Here in South Australia we often have only one or two species of a complex or a genus but this is not necessarily the case in the rest of the country. One such instance is Urochilus sanguineus (syn Pterostylis sanguinea) or Maroon Banded Greenhood. It is possible that we may have a subspecies or possibly the Mallee form but nothing like the occurrence of  this species in Western Australia where it is but one of many in a complex of several – the Pterostylis vittata complex or Banded Greenhoods*.

Below, with permission, is Andrew Brown’s post on Facebook with notes and images about the complex as it is understood in Western Australia.

The Banded Greenhood complex in Western Australia

Members of this complex grow 150 to 450 mm high and have up to 20 green, brown or reddish-brown white banded flowers characterised by their, short, broad lateral sepals which are joined at the base and a small, insect-like labellum which flicks up when touched. In all species, flowering plants lack a basal rosette of leaves while non-flowering plants have a flattened, ground hugging, rosette of leaves.

Banded greenhoods are found over a wide geographic range between Binnu north of Geraldton and Eyre on the Great Australia Bight, growing in shrublands, woodlands, forests and shallow soil pockets on granite outcrops.

There are ten Western Australian species in this complex, seven of which are formally named. However, as two were named as species of Urochilus, a genus not recognised in Western Australia, only five of these names are currently recognised here. In Western Australia, all members of the complex are considered to be in the genus Pterostylis.

All are winter flowering.

Pterostylis concava

Pterostylis concava AB

Distinguished from other members of the complex by its prominently cupped lateral sepals and the upturned projection near the base of the labellum. Found between Bindoon and Mt Barker.

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Pterostylis crebriflora

Pterostylis crebriflora AB.jpg

Distinguished from the similar Pterostylis sanguinea by its often shorter stature and slightly larger flowers which are crowded in a dense spike near the top of the stem. Found on the Darling Scarp near Perth.

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Pterostylis sanguinea

Pterostylis sanguinea AB.jpg

A very common species that is also found in South Australia, Tasmania and Victoria. It was named from specimens collected in South Australia. The species is similar to Pterostylis crebriflora but is usually taller with smaller, more widely spaced flowers. Flower colour is variable and it is not uncommon to find brown and green flowered forms growing alongside one another. Found over a wide area between Mullewa and Eyre on the Great Australian Bight.

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Pterostylis sanguinea (Mallee form)

Pterostylis sanguinea mallee form AB.jpg

An unnamed member of the complex distinguished from Pterostylis sanguinea by its short stature and few flowered inflorescence. Found over a wide range from the Stirling Range to the north of Esperance.

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Pterostylis sp. Coastal

Pterostylis sp coastal AB.jpg

Some consider this to be a form of Pterostylis sp. small bands but it is usually taller with more widely spaced flowers. The sepals are also narrower and often slightly cupped. Found mostly in near coastal areas between Dongara and Bunbury. Similar looking plants have also been found further inland between Brookton and Mt Barker.

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Pterostylis sanguinea (green flowered form)

Pterostylis sanguinea green flowered form AB.jpg

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Pterostylis sargentii

Pterostylis sargentii AB

A common, widespread species, distinguished from other members of the complex by its smaller flowers and fleshy, tri-lobed, frog-like labellum. Found over a huge geographic range between Northampton and Mt Ney, north of Esperance.

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Pterostylis sp. Crowded

Pterostylis sp crowded AB

 

A widespread species named Urochilus atrosanguineus in June 2017. Distinguished from the similar Pterostylis sanguinea by its more robust habit and larger dark reddish-brown flowers. It is also similar to Pterostylis crebriflora but generally flowers earlier and has more widely spaced flowers in a longer spike. Found between Wongan Hills and Katanning with rare, scattered populations on the Swan Coastal Plain.

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Pterostylis sp. Eyre

Pterostylis sp Eyre AB

A distinctive member of the complex distinguished from others by its pale coloured flowers. Like Pterostylis sanguinea (mallee form) it has a short stature and few flowered inflorescence. Found along the coast between Toolinna Cove and Eyre on the on the Great Australian Bight.

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Pterostylis sp. small bands

Pterostylis sp small bands AB

A northern species named Urochilus orbiculatus in June 2017. It is regarded by some researchers to be a form of Pterostylis sp. coastal but is usually shorter with a more densely crowded spike of flowers. Its sepals are also broader, more rounded and flattened rather than slightly cupped. Found north of Perth between Cataby and Binnu.

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Pterostylis vittata

Pterostylis vittata AB.jpg

A widespread species distinguished from other members of the complex by its less fleshy, paler coloured, predominantly green flowers and narrower, elongated, slightly cupped sepals. The flowers also have a more translucent appearance. The typical form is found between Bindoon and Balladonia. There is a northern form with a shorter spike of often fawn coloured flowers found between Cataby and Binnu.

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It should be noted that in South Australia and Victoria U. sanguineus was originally called P. vittata but that species is now recognised as being endemic to Western Australia.

*As an aside, the common name Banded Greenhoods is used in South Australia for the subgenus Bunochilus (previously Pterostylis longifolia which is now considered endemic to New South Wales).

 

Gleanings from the Journals: Terrestrial Potting Mixes

The following article by Les Nesbitt was published in May 2017 Native Orchid Society of South Australia Journal Volume 41 No 4. The article relates to Australian Native Orchids.

Suggested potting mixes for potted native terrestrial orchids have changed greatly over the years as some ingredients such as peat moss have become too expensive or difficult to obtain. Basic requirements are that the mix should be free draining yet retain moisture and should have an organic component that breaks down slowly and does not go mushy in winter. Most species are not too fussy and will grow in a variety of mixes.

Those tubers that desiccate in summer do better in a heavy mix that contains clay. Examples are Diurus behrii, D. punctata and Pterostylis nutans.

Tubers that rot easily in wet soil in Spring prefer an open coarse sandy mix. An example is Thelymitra antennifera.

A dry mix containing a higher proportion of sand is usually recommended for Caladenia and Glossodia species grown in pots. In contrast these orchids grow in clay soil on my property in the Adelaide Hills but there excess water can run off. In pots, excess water has to drain through the potting mix.

An organic component is vital to feed orchid fungi.

Some Basic Ingredients:

  • Washed sand with rounded particles. (Not sharp sand as this sets hard in summer.)
  • Soil (sandy loam, clay based loam, mountain soil)
  • Native seedling mix (Bark based – sieve to remove splinters)
  • Native potting mix (can be sieve* to remove larger particles)
  • Chopped and sieved* gum leaves
  • Perlite or isolite (but will make tubers harder to identify at repotting time)
  • Composted leaf mould & buzzer chips (but needs to be gathered now for use next summer)
  • Cauarina (She-oak) needles chopped for surface mulch

Some Suggested Potting Mixes

  1. ANOS-Vic dry mix – 2 parts coarse sand, 1 part coastal sandy loam, 1 part composted buzzer chips, 1 part leaf mould
  2. 100% native potting mix. (Works for drought resistant tubers, viz. Pterostylis curta & P. pedunculata)
  3. Native potting mix (sieved*) and isolite
  4. Native potting mix and sand
  5. Les Nesbitt’s current mix of 50% sand, 20% hills soil, 25% seedling potting mix (sieved), and 5% chopped & sieved* string bark gum leaves.
  6. Dry mix, 50% coarse sand, 25% perlite & 25% native potting mix
  7. Heavy mix, 50% clay soil, 30% sand and 20% organic matter

* Use a 5mm sieve

thelymitra-plants-1.jpg

Thelymitra in cultivation