Genes, seasonal conditions or pure chance?

Leo Davis is an orchid hunter.  He is meticulous in his observations and notes details that many of us may miss.  In this article he muses upon the variations that he sees in the field.

You, as I do, must occasionally come upon an orchid or an orchid event that is a little outside normal experience.  When I do, I wonder whether this is a purely chance event or is it caused by recent local environmental factors, or is it due to the genes of the plants.  Or a combination of these?

I’ve been watching a couple of patches of fire orchids (Pyrorchis nigricans) that many of you will be familiar with, one at Knott Hill N.F.R., the other at Monarto C.P., where a few plants flower every year, without the normally required stimulation by fire.  I need to check whether it is the same plants that flower each year.

Pyrorchis nigricans.jpg

Pyrorchis nigricans (Fire or Undertaker Orchid) Photo: Leo Davis

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The tall leek orchid (Prasophyllum elatum) puts up leaves at Scott Creek C.P. every year but does not flower. A fire swept through in early 2014 and most plants flowered in October.  They’ve not flowered since.  But over at Ramsay Way, west of Pt. Vincent, a few plants flower each year without fire.  I assume genes are involved.

Prasophyllum elatum

Prasophyllum elatum (Tall Leek Orchid) Photo: Leo Davis

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In April 2014 I chanced upon a patch of Adelaide Hills parson’s bands (Eriochilus collinus), along Moore’s Road, at Morialta C.P., in which the majority of plants had three flowers per stem. Was this because of favourable conditions or genes? Over the next two seasons I saw only the occasional double header and mainly single flowered plants. I will continue observations and records.   

 Eriochilus collinus

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In July 2015 I found a dense patch, about 3 m2 in area, of hundreds the common mallee shell orchid (Diplodium dolichochilum), in Ferries-McDonald C.P. As usual less than ten plants were in flower, but two of them were double headers.  I’ll be checking this season and expect this not to be a chance event but one due to genes.

Diplodium dolichochilum

Diplodium dolichochilum syn. Pterostylis dolichochila (Slim Tongued Shell or Common Mallee Shell Orchid) Photo: Leo Davis

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On May 27, 2012, Bob Bates led a NOSSA outing to Scott Creek C.P. and as ever, when he leads, we saw and learned a lot.  He showed us a patch of fringed hare-orchids (Leporella fimbriata) that he assured us should not be growing there on that steep rocky site and that the plants would not flower most years.  Unfortunately he was right, as usual.   I could not find plants in 2013 and 2014 and it took three searches in 2015 to find a very few leaves. On May 10 this year, over an area of less than 10 m2, I found perhaps 50 leaves and just seven plants in flower.  Three of these had three flowers and a tiny unopened bud (check the photo) and the others were doubles.  I’ve never seen a triple flowered plant in hundreds I’ve seen at Knott Hill N.F.R.  Are genes in an isolated population at play here?  Given the paucity of flowering at this site, it may take me years to sort this one out.

Leporella fimbriata

Leporella fimbriata (Fringed Hare  or Ballerina Orchid) Photo: Leo Davis

Leo Davis.

 

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Leptoceras and Leporella – Why are they in different genera?

QUESTION: Are there more than one species called Hare Orchid? This one [Leporella fimbriata] looks different from Leptoceras…?  Why are they in different genera?

 

ANSWER:

Originally they were described the genus Caladenia but as the knowledge information increased other genera were created.  Thus Leporella fimbriata was put into Eriochilus, as Eriochilus fimbriatus (1882), then Leptoceras fimbriata and finally into its own genus Leporella (A S George 1971).  Caladenia menziesii became Leptoceras menziesii.

This does not answer the why of the question which is about classification but Jones (2006) is helpful when he says:

“Plant classification systems rely on interpreting and measuring the features in one group of plants and comparing these with another group, either seeking difference or similarities.  Studies in orchids are usually biased heavily towards features of floral morphology but recent studies have revealed the importance of vegetative features in the roots, stems and leaves.  The most successful classification system is one that is balanced and based on a wide range of vegetative and floral features.”  To add to this list is the molecular studies being done on orchids.

This means the authors advocating change need to clearly show why a name change and/or a new species is warranted.

For instance, Fitzgerald gives the following reason for not including Leporella fimbriata in the Caladenia genus

“Leaves much more frequently observed than flowers.  It is with great reluctance I depart from the naming in ‘Flora Australiensis’ [author Bentham, 1863 – 1878], but I cannot concur with the inclusion of this with Caladenia, and have place it in Lindleys’ Leptoceras for the following reasons: Leaf or leaves not those of Caladenia.  In Caladenia I have never seen more than one leaf, always thin and usually hairy; in this plant leaf thick, hard and shining, occasionally two.  In Caladenia tubers are generally numerous, in L. fimbriata I have only observed one.  The labellum, is without the characteristic glans and is not of the form obtaining in Caladenia, the stigma is very different in form being triangular and deep sunk, the upper parts overhanging, not oval and shallow; and the flowers have the peculiarity of drying and continuing in a state hardly to be distinguished from the fresh flowers long after the seed has been shed.  It approaches C. menziesii only (so far as I can see) in having erect linear-clavate petals, in which C. menziesii is itself peculiar, L. firmbriata seems to come near to Eriochilus than to Caladenia but differs from it again” Quoted from Emily Pelloe Western Australian Orchids 1930

Concerning Leptoceras menziesii, Bates & Weber have made the following statement:

“True Caladenias have hairy scapes and hairy leaves.  (C. menziesii now believed to belong to a separate genus is glabrous)”.

Even though they are not Caladenia, why not have them in the same genus for both have glabous (without hairs) leaves, more leaves than flowers, erect spathulate (spoon shaped) glandular petals, colony forming, similar distribution.

Leporella fimbriata  in patch

Leporella fimbriata – note the absence of leaves and the dry sandy conditions [Photo: R Lawrence]

Leptoceras menziesii in patch

Leptoceras menziesii – note the abundance of leaves [Photo: R Lawrence]

There are similarities.  In fact, Bates (2011) calls them sister genera but despite the similarities there are enough differences to recognise them at genus level at present including “different flowering times, different mycorrhizal fungi associations and different pollination” some of which are detailed in the chart below.

 

Feature Leptoceras Leporella
Pollination Strategy Strategy unknown

Native Bee

Strategy pseudocopulation

Winged male ants (Myrmecia urens)

Myrmecophyte – lives in mutualistic association with colony of ants
Labellum Curved white with red stripes

Has calli

Wider than longer, purple and green

Has no calli

Flowering Time Spring (September to November) Autumn (March to May)
Habitat Shaded sites – moist gullies; scrub, heath, woodland and foret Open sites – acid sands, light scrub, stringybark
Leaf Emergence Leaves emerge before flowering Leaves emerge after flowering

 

Leptoceras menziesii (Rabbit Ears Orchid)

Leptoceras menziesii (Hare Orchid or Rabbit Ears Orchid) after a fire, [Photo: R Lawrence]

REFERENCES:

https://en.wikipedia.org/wiki/Myrmecophyte accessed May 13 2016

http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&name=Leporella_fimbriata accessed May 13 2016

http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&name=Caladenia_menziesii accessed May 13 2016

Pelloe E, Western Australian Orchids 1930

Bates R & Weber J, Orchids of South Australia, 1990

Bates R Editor, South Australia’s Native Orchids 2011

Martin A, The Vocabulary of Orchids: an Amateur Perspective 2005

Rogers R, South Australian Orchids 2nd Ed 1911

Jones D, A Complete Guide to Native Orchids of Australia including the Island Territories 2006

March 2016 Winning Photograph

1603 sm JS Arachnorchis sp

We frequently receive entries from Western Australia but this month our entries were from both the west and the east. Allen Jennings entered a Calanthe triplicata (Christmas Orchid) from New South Wales. Pauline Meyer’s was from the west, (Western) Flying Duck Orchid, Paracaleana nigrita. The other entries were South Australian, Jenny Pauley’s recently photographed Leporella fimbriata (Fringed Hare Orchid), Greg Sara’s Thelymitra rubra (Common Pink Sun Orchid) and Judy Sara’s Plumatochilos sp. (Bearded Orchid) and Arachnorchis sp. (Spider Orchid).

The winning photograph was Judy’s Spider Orchid. Obviously it was one of the Green Comb Spider Orchids – A. dilatata complex. Of this group there are about a dozen possibilities. Knowing the location, Mt Boothby, helped to narrow the options with the most likely candidate being Arachnorchis stricta but it wasn’t convincing. It would appear that the tips of the sepals may have been chewed off when in bud.

A distinguishing feature of this species is that there are no clubs or osmophores on the sepals. Other species of this complex have clubs. Another feature is that the dorsal sepal is bent over the column unlike many other green combs which have an erect dorsal sepal. The features that caused doubt were lateral sepals looking droopy instead of being characteristically stiffly held out but dry conditions could cause this. The other was that the labellum did not strictly fit the description of A. stricta but then again it is a variable species.

The conclusion was a possible hybrid but there is no information on the likely parents or that is an atypical A. stricta that may have been damaged in bud.

This is an example of the difficulties that can occur when attempting to identify a plant from one photograph.

Reference:

Personal communications Thelma Bridle (NOSSA Conservation Officer)

Personal communications Bob Bates

Bates, R. J., ed. (2011). South Australian Native Orchids. Electronic version, 2011. NOSSA

Rules of entry:

The subject matter must have something to do with Australian orchids.  Any format is acceptable including Photo shopped images, artwork, etc

How to enter:

Email nossa.enquiries@gmail.com – jpg as large as you are able to send it, preferably A4 ratio for printing

Post: PO Box 565, Unley, 5061

Bring in to the meeting