Genus Plumatichilos

This week’s blog is from the Journal of the Native Orchid Society of South Australia, Volume 42 No 8. Leo Davis has been doing a series of articles aimed at helping members learn how to identify the orchids.

This article is about Plumatichilos, one of the segregate genera of Pterostylis. It has an unique labellum which sets it apart from the other Greenhoods. Leo wrote this article soon after David Jones named them in the Australian Orchid Review.  Will these names be accepted or not is a matter of waiting and seeing but it should be noted that they have been in manuscript form for many years. At the time of writing, they are not in the South Australian eflora.

Both the species discussed in Leo’s articles are from the Plumatiochilos plumosum complex or group.

Plumatichilos sp. Mallee Bearded Greenhood =Plumatichilos multisignatus

Plumatichilos sp. Woodland Bearded Greenhood = P. foliaceus

Unless otherwise noted, all images are Leo Davis.

Genus Plumatichilos.

Back in 1990 Bates & Weber placed all greenhood orchids in genus Pterostylis(1. pp118-143) where some of you and all Australian State Herbaria and certainly Janes & Duretto (3. pp260-269) would have them still be.  In 2001 Szlachetko erected the genus Plumatichilos.  In his Guide(4. pp286-339), Jones divided the greenhoods into 16 separate genera, these in two groups, each of eight genera.  One group all have the lateral sepals directed downwards (including Bunochilus and Urochilus) and the other eight all have them directed upwards (deflexed, as in Diplodium and Pterostylis).  Even those of you who reject the splitting and creation of the extra genera will concede that those placed in Plumatichilos, which have downward directed and partly fused lateral sepals (forming a synsepalum), are strikingly different in appearance to any other Pterostylis species.  The most obvious distinguishing features are the unique labellum and the two openings to the galea.

I had known just two species of Plumatichilos, both of which were undescribed.  I could recognise and distinguish them essentially because they grew in very different habitats and locations.  I used Bates’ tag names, Mallee Bearded Greenhood (Plumatichilos sp. Mallee Bearded Greenhood) (3. pp913-4) and Woodland Plumed or Bearded Greenhood (Plumatichilos sp. Woodland Bearded Greenhood)(1. pp915-916).   In recent weeks both (along with two other South Australian species) have been formally described.  They are now, respectively, Plumatichilos multisignatus(5. pp33-35) (Fig. 1) and P. foliaceus(5. pp30-32) (Fig. 2).  But, to a large extent, I still identify them more by the locations in which I find them than, to my eye, clearly discernable physical features.

Fig 1 P multisignatus Fig 2 P foliaceus
Fig. 1. Plumatichilos multisignatus. Monarto. Sept 10, 2012. Fig 2. Plumatichilos foliaceus. Para Wirra. Sept 11, 2013.

I had no idea what ‘barrier trichomes’ were but I saw that Jones listed them as the last of 13 dot pointed characters of genus Plumatichilos(5. p26).  Trichome simply means a hair growing from a plant epidermis.  They can be unicellar or multicellular and branched or unbranched.  The ‘barrier’ refers to its capacity to block and direct a pollinating insect to an exit path that puts it in the right posture to transfer a pollinium to the stigma (sticky receptive female part of flower).

Fig 3 Bunochilus prasinus June Niejalke Janes & Duretto, who reject the splitting of genus Pterostylis, divide it into two subgenera using the absence (subgenus Pterostylis) or the presence (subgenus Oligochaetochilus) of barrier trichomes on the column wings(3. pp262).  They place what I call Plumatichilos in the section V, Catochilus, of subgenus 2 Oligochaetochilus(3. pp266), and, yes, I see your eyes glaze over.  To them the Adelaide Hills ‘plum’ would be Pterostylis, subg. 2 Oligochaetochilus, Sec. V. Catochilus, species foliaceus.  Learning what ‘barrier trichomes’ are had me go back searching my photo library and I found images of the barrier trichomes in Bunochilus flowers that I had not previously spotted.  I have used and annotated a detail sent to me by June Niejalke. (see Fig. 3).

Fig. 3. Bunochilus prasinus. Sherlock (Type location for the species). Photo by June Niejalke.

As with all ‘true’ Pterostylis, the dorsal sepal and the two lateral petals, of the upside down flowers, are formed into a galea or cap (Fig. 1).  They are fused so closely that it can be hard to discern the join between the sepal and the comparatively small petals, especially in some less clearly striped flowers. (Figs. 1 & 2).

The typical Pterostylis galea has a single opening but in Plumatichilos there are two, a lower one, from which the uniquely formed labellum protrudes (and through which the pollinating male gnats enter) and an upper one (through which the pollinators exit) (4. p335), guided by the barrier trichomes (Fig. 4).  Through this upper opening you can observe the top of the column, including parts of it, the pollinia, the barrier trichomes, column arms and sometimes the stigma.  Two crossed filaments, in front to the pollinia, are column arms.

Fig. 4. Plumatichilos foliaceus. Scott Creek C.P. Sept 2015.

Fig 4 P foliaceus

 

Fig 5 P foliaceus.jpg The labellum (the modified third petal) (Figs 1, 2 & 5) is unlike that of any other Pterostylis sp.  It has a slightly flattened filament having a reddish-brown apical knob and two or three types of hairs along its length.  Jones describes the labellum of P. foliaceus as having three types of hairs(5. p30).  You may be able to see the short white ones (1 mm) at the base of the labellum in Fig. 5.  The longer (5-7 mm) yellow ones along the most of the length of the labellum are easy to see.  I am not sure that I can distinguish the shorter proximal (near point of attachment) yellow ones (1.5 mm).  In P. multisignatus Jones describes just two types of labellum hairs(5. p33) with the white basal ones absent, and two sorts yellow hairs, proximal ones to 1.2 mm and longer ones 5-8 mm.  To my eye, this character, two or three types of labellum hairs, is the only objective, rather than subjective , distinguishing feature between the two species that I regularly observe.

Fig. 5. Plumatichilos foliaceus. Scott Creek C.P. Sept 26, 2015.

In Fig. 5, I think that you can see that the hairs arise, in two parallel rows, not paired, from the sides of the flattened shaft of the labellum filament.

Fig 6 P foliaceus Fig. 6. Plumatichilos foliaceus in early bud. Scott Creek C.P. August 29, 2018.

Another generic character is ‘leaves sessile (no stems), ascending to erect, often with whitish or yellowish interveinal areas.’ (5. p26)  You may need to look very closely, in Fig. 6, to see these ‘windows’, mainly at the bases of the stemless leaves. 

 

References:

  1. Bates, R.J (2011). South Australian Native Orchids, DVD Issued by the Subediting Committee (NOSSA) on behalf of the
    Native Orchid Society of South Australia Incorporated.
    2. Bates, R.J. & Weber. J.Z (1990). Orchids of South Australia, A. B. Caudell, Government Printer, South Australia.
  2. Janes, J.K. & Duretto, M.F. (2010), A new classification for subtribe Pterostylidinae (Orchidaceae), reaffirming
    Pterostylis in the broad sense. Australian Systematic Botany, 23, 260–269.
  3. Jones, D.L. (2006), A Complete Guide to the Native Orchids of Australia, Reed New Holland, Australia.
    5. Jones, D.L. (2018), Six new species of Plumatichilos (Orchidaceae: Pterostylidinae) fromSouth-eastern Australia and a
    new species from New Zealand, Australian Orchid Review 83(4): 26-44.

Other articles about Plumatochilos can be found here and here.

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Orchids in the Snow?

It’s Christmas and usually, despite Australia’s hot climate, we associate Christmas with snow and cold but we don’t tend to associate them with orchids. And yet, for Australia we do have not one but two Christmas flowering orchids in snow country, that is, on the isolated sub-Antarctic Macquarie Island, an island where “[r]ain and snow are frequent, with only a few days each year with no precipitation”. Admittedly at this time of the year, being summer it is warmer with an average temperature of 7.9degrees Celsius.

The first species was only discovered in 1978 and not recognised as an unique species until 1993 when it was named Corybas dienemus (syn. Nematoceras diemenum). Previously it had been linked with Corybas macranthus.

The second orchid species is  Corybas sulcatus (syn. Nematoceras sulcatum) and this species, possibly the world’s rarest orchid, has gone travelling. Staff from the Royal Tasmanian Botanical Gardens have manage to collect and amazingly propagate the seed.  Amazingly because orchids, particularly the terrestrial orchids, are difficult to grow. It is now flowering, this Christmas season, but under very carefully controlled conditions in Hobart.

Click here and here to see images and read about this amazing journey.

So Christmas, orchids and snow do go together in Australia, albeit in the far flung island of the south.

Corybas sulcatus (Grooved helmet-orchid) is one of two endemic orchids which occur on Macquarie Island (Photo: Royal Tasmanian Botanical Gardens) Image Source

Reference

https://en.wikipedia.org/wiki/Nematoceras_dienemum accessed 23 December 2017

http://www.antarctica.gov.au/living-and-working/stations/macquarie-island/location/climate-weather-tides accessed 23 December 2017

http://www.antarctica.gov.au/news/2017/sub-antarctic-orchid-shows-true-colours-far-from-home accessed  23 December 2017

 

2017 October Cultural Notes

Steve Howard’s October Australian Epiphytes and Terrestrials Orchids Cultural Notes for Adelaide’s conditions.

Epiphytes

  • October sees many native epiphytes finish flowering and shortly it will be the best time for potting on and division as new growths are due shortly. The earlier you start, the more time the orchid has a chance to initiate new growth and mature it in time for next years flowering.
  • Remove spent flowers as leaving them on the plant in wet and humid conditions leads to rot caused by botryitis.
  • Be aware that aphids are in big numbers now and will cause grief to flowers and new growths.
    • Malathion at 1 ml/ litre of water will knock them out.
    • Repeat fortnightly for 6 weeks to break the breeding cycle.
  • Apply lime to plants grown in bark to counteract acidity.

Terrestrials

  • Most terrestrials nearing completion of the season.
  • Start drying off once leaves start yellowing. Keep water up to those staying green.
  • Additional shade helps now as suns intensity increases
Epiphytes in flower (1)

Annual NOSSA Spring Show

2017 September Cultural Notes

Steve Howard’s September Australian Epiphytes and Terrestrials Orchids Cultural Notes for Adelaide’s conditions.

Watering

Epiphytes

Mounts daily. Generally moistening roots only.

Pots weekly. Small pots twice weekly depending on weather.

Terrestrial

Pots can dry out faster on warmer days so keep a watch on conditions. Note some terrestrials will commence summer dormancy towards the end of the month. Those that do show signs can have water reduced somewhat.

Feeding

Terrestrials

Weak organics like Seasol and Powerfeed applied in low doses can benefit colony type greenhoods.

Epiphytes

Low nitrogen always best for native epiphytes. Top up epiphyte  pots with dolomite lime and a dash of blood and bone. Seasol a useful additive now as new seasons root start.

Pests and Disease

Epiphytes

Botrytis will rot new buds in cold damp weather as fast as it attacks new growths from now. Aphids will increase sharply this month and favour new growth and spikes.  Pyrethrum sprays eco friendly and work well, so does a hose but dry spike straight after.

Terrestrials

Some terrestrials will rot this month if conditions have been too wet or stagnant over winter. Note this for next season and add more drainage if this has been an issue.

General Advice

Keep flowering plants under cover to enjoy as can be rather wet and cold as well sunny and warm this month. Start repotting and division once flowering finished to give plants longest possible time to establish over new growing season.

Time to get busy and take note of the jobs of potting and division to be done. Sept and October are the best months to work on the collection before the hot weather sets in.

Do you have small slugs and snails in your pots?  Get a cheap coffee grinder and grind up your snail pellets. Sprinkle in the pot and water them in. Bite size for micro slugs and the baits get right into where they hide.

[Terrestrials are not repotted until summer – Steve will have more on that later]

Pterostylis 'Nodding Grace'

2017 August Cultural Notes

Steve Howard writes cultural notes for Adelaide conditions. These are his notes for August; for both epiphytes and terrestrials.

WATERING

Mounts daily.

Pots weekly. Small pots twice weekly depending on weather. Drier conditions for hot cold types. Terrestrial pots can dry out faster on warmer days so keep a watch on conditions.

FEEDING

Epiphytes: Recommending feeding towards months end as days lengthen. Many plants in strong spike growth and flowering now.

Terrestrials generally don’t need to be fed although weak organics like Seasol and Powerfeed applied in low doses can benefit colony type greenhoods.

PESTS AND DISEASES

Epiphytes: Botrytis will rot new buds in cold damp weather as fast as it attacks new growths from now. Aphids will increase sharply this month and favour new growth and spikes.  Pyrethrum sprays eco friendly and work well, so does a hose but dry spike straight after.

Some terrestrials will rot this month if conditions have been too wet or stagnant over winter. Note this for next season and add more drainage if this has been an issue.

 

GENERAL

Epiphytes: Keep flowering plants under cover  to enjoy. Soon will be the time to start thinking about re-potting and division as spring nears.

Keep flowering terrestrials out of strong winds and heavy rains as flower stems on some varieties are quite weak when grown in cultivation

Additional:

Later August will produce some warmer drying days as spring nears. Ensure small pots and plants don’t dry out at this time. Good time to check out seedling lists and prepare orders to ensure your plants arrive at the commencement of a new growing season.

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Q&A: How do I deal with mould in my orchid flasks?

Question:

I have recently been learning about propagating orchid via flasks but I have mould in some of the flasks.

Orchid Seeds in flask with mould

Flask with orchid seeds and mould

There is mould in the flask with orchid seeds and also in the flask with Diuris tricolour in bulbs.  The bulbs are almost ready for deflasking.

Diuris tricolour in flask

Flask of Diuris tricolour (no mould) – these will be deflasked later this year.

 

What can I do?

Answer:

With a home laboratory, no matter how careful one is, mould can still contaminate the jars of agar. If mould occurs when the orchids are still in seed, then the whole jar needs to be discarded.  The seeds will not survive.

With the Diuris flask, as they are almost ready for deflasking, pot them out straight away. This needs to be done within 10 days of the mould appearing. The weather (March, 2017, South Australia) is still a little too warm but if left in the flask, the plants will die.  Potting them out may give them a chance of survival.

When deflasking, it is important to rinse all the agar off the bulbs before potting on as normal. Once potted, it could help to cover the pot with a cut down clear drink bottle with the lid removed. This will allow some air to circulate. Keep the pot in a shady spot.

Diuris tricolour in pot with bottle top cover

Potted Diuris tricolour with protecting bottle cover

Will it survive in the pot? Hopefully it might but at least the plants have a better chance of survival then if left in the flask where it would surely die.

 

Spiranthes alticola

At this time of the year there are not many orchids flowering in South Australia but one that is just finishing is Spiranthes alticola. The genus Spiranthes, commonly known as Ladies Tresses, is found throughout Australia, Eurasisa and the Americas.The following description is an extract from South Australia’s Native Orchids 2011 DVD which is available from the Native Orchid Society of South Australi. 

Spiranthes alticola D.L.Jones

Swamp Spiral Orchid

Etymology: The name alticola means high dweller, referring to its distribution in Eastern Australia, in west Victoria and South Australia’s South East.  It also grows near sea level.

Synonyms: Previously included in Neottia australis R. Br., S. sinensis (Pers.) Ames and S. australis R.Br.

 

 

(These two pictures show the variation in colour.)

Description: Leaves 3-5, narrow lanceolate, shiny, erect at the base, to 15 cm long. Flower stem to 45 cm tall, slender, flexible, with several sheathing bracts.  The flowers are numerous in a dense spiral, pink with a white labellum, rarely all white.  Segments are 6-10 mm long, sepals somewhat triangular, petals lanceolate, together forming a short tube, the tips free and recurved, and the lateral sepals divergent.  Labellum with a broad, decurved crisped, pellucid mid-lobe, side-lobes erect small.  The flowers are faintly fragrant.

spiranthes-alticola-leavesrwl-92

(Leaves of Spiranthes alticola)

Flowering: Dec – Jan – Feb.

Similar Species: S. australis, S. sp. Late selfing-white.

Distribution: SL, KIx, SE; NSW, Vic, Tas.

Confined in South Australia to a few high rainfall, near coastal, often mountain locations, southward from the Adelaide Hills in the Southern Lofty region, extinct on Kangaroo Island, (one record only), and South East; also in New South Wales, Victoria and Tasmania.

Habitat: Restricted to peaty bogs and swampy creek-sides, often in locations that are inundated throughout winter; in some areas surviving in paddocks grazed by stock.

Distinguishing Features:  S. australis, which is from the eastern states and is not strictly a swamp plant, has smaller darker pink flowers with a narrow labellum.

  • The two South Australian forms treated here are regarded as distinct species as where they are sympatric they begin flowering at different times and do not intergrade. S. alticola is the more delicate of the two.

Notes:  The best specimens are found on mowed firebreaks adjacent to swamps.  When vegetative reproduction produces two clonal plants next to each other the spiral arrangement of one is often a mirror image of the other.  See Gallery.

Native bee pollinators work the spikes from the bottom upward but as the stigma becomes receptive well after the pollinia have matured this mechanism helps ensure outcrossing.

Plants do well in cultivation if kept moist over summer.

Conservation Status:

Status in Legislation: Not listed nationally, rare in South Australia.

Suggested Status: Rare in South Australia but more common in the Eastern States

 

Notes on Dipodium pardalinum at Silverton

A site, along Rarkang Rd, Silverton, leading into Talisker Conservation Park, was visited on December 29, 2012, January 2, 2014, January 16, 2015 and January 9, 2017.

In the earlier years about 20 specimens of Dipodium pardalinum were found with 18 (plus 3 beheaded) in 2015.  A small number of D. roseum was located in 2012, none in 2014, one in 2015 and none at all in 2017.

In 2017 there was bumper crop of D. pardalinum and Ed Lowrey, Helen McKerral and I counted 124 flower spikes.  This may represent only 122 plants because in two instances there were two spikes emerging from one tuber (see image).  It is possible that other closely placed flowers were also growing from a single tuber. This same phenomenon was observed in two cases, with D. roseum, at Hender Reserve, Stirling, on January 12 this year.

All spikes of D. pardalinum this year were found on the verges of Rarkang Road or nearby inside private property in small holdings, with houses, adjoining the road, apart from two spikes only, just inside the Talisker Conservation Park, where Rarkang Road heads into it.

The genus Dipodium is much more varied than I realised.  Our DVD, South Australia’s Native Orchids, only deals with the ‘leafless saprophytes, mycophytes or hemiparasites’.  If you go to ‘Native Orchids of Australia’ (Jones, 2006), you will find that among the terrestrial species there are both leafless species (as with the local D. pardalinum and D. roseum), that are impossible to cultivate and one species with leaves (D. ensifolium), found from Cooktown to Ingham, in Qld.  It is easy to grow in a pot.  Bob Bates told me that it is grown here in Adelaide, preferring a heated glass house, but has been grown successfully in gardens.  And then there is a leaved species, D. pandanum, of limited distribution in Qld, that can be either terrestrial or epiphytic, growing up to 5 m in length.  Old pieces that break off and fall to the ground, nestle in the leaf litter and put out new shoots that eventually climb into the trees.  It is easy to grow in a pot (in the right climate).

Leo Davis.

Dipodium pardalinum.
Rarkang Rd, Silverton, Jan 9, 2017.
 d-pardalinum

 two in one spike.jpg Two spikes of Dipodium pardalinum emerging from one tuber.

Rarkang Rd, Silverton, Jan 9, 2017.

A clump of Dipodum pardalinum spikes with at least two emerging from one tuber; see photo above.

Rarkang Rd, Silverton, Jan 9, 2017.

 Pardalinum spike.jpg

 Roseum and Pardalinum.jpg

Dipodium pardalinum (labellum white with dark pink spots) growing intertwined with D. roseum, (labellum pale pink with dark pink stripes).

Rarkang Rd, Silverton, Dec 29, 2012.

 

Growing Leek Orchids – Is it Possible?

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.

Prasophyllum murfettii sm

Prasophyllum murfettii (Denzel’s Leek Orchid)

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: marc.freestone@rbg.vic.gov.au 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.

Orchid Seed Conservation

There are many different activities involved with orchid conservation.  In situ conservation consists of looking after the orchids where they are growing; maintaining and protection of habitats and ecological systems.  On the other hand ex situ conservation is caring for the orchids in cultivation in a similar way that zoos maintain an animals species that is extinct in the wild.

For the orchids one form of ex situ conservation is via seed collection and the propagation of new plants. With many of our terrestrial orchids this is not an easy task but here in South Australia an attempt is being made with four of our endangered orchids.

Unlike some of our terrestrial orchids these are ones which we have not been able to grow.  There is a collaborative effort co-ordinated through the South Australian Seed Conservation Centre (Seedbank) to change this.  Amongst the people helping the Seedbank are members of the Native Orchid Society of South Australia, students from Kildare College and Dr Noushka Reiter of the Royal Botanic Gardens Melbourne.

On July 30 2016, Dan Duval of the Seedbank was interviewed by Jon Lamb on Ashley Walsh’s ABC 891 Adelaide Talkback Gardening program.  It is an informative interview and well worth the listen.

For more information on the work of the Seedbank, visit their website

Video as heard on Talkback Gardening with Jon Lamb and Ashley Walsh – Saturdays from 8.30 on 891 ABC Adelaide.