Meet the Great Greenhoods!

In my last posting I featured a few greenhood orchids, but I realised later that they probably won't be familiar to readers outside of Australia, and even to many people living here. I thought I might rectify that today. As a group they are almost restricted to Australia, and they are fairly modest and inconspicuous. They are over 200 strong however, and I find them fascinating. As I mentioned in the last posting, there is some turmoil here over the taxonomy; they have always been lumped into just one genus, Pterostylis, but recently, and controversially, the genus has been divided into 16 genera by Jones and Clements. I shall use their genus names here, because that's how they appear in Jones' mighty Complete Guide to Native Orchids of Australia, the only comprehensive work.

They seem to be an old group with no close relations; indeed they are so specialised that they are not always immediately recognised as orchids. To explain just how they're composed, allow me to give you a brief revision of the basics of an orchid flower, using a more 'standard' flower type.

Diuris punctata, Tallong, New South Wales.
(Please forgive the washed-out image - I must find a better way of labelling pics and getting them to this format.)
Unlike most flowers, orchids (and lilies) have sepals - the outer ring of flower parts - which are as large and colourful as the petals. There is one dorsal sepal at the top of the flower, and two lateral sepals lower down. There are two dorsal petals (which don't look as though they arise inside the sepals, but look at the top flower), with the third petal forming an insect landing platform called the labellum (lip). And that'll do for now!

In greenhoods, the two dorsal petals and the dorsal sepal strongly overlap to form the hood, or galea.

Summer Greenhood, Diplodium decurvum, Tidbinbilla Nature Reserve near Canberra.
The hood, or galea, covers the top of the flower; it is hard to make out the three different parts of it.

This picture also shows two other features of greenhoods. One is that the lateral sepals are fused, unlike those of other orchids like the Diuris above. The other is the essential labellum, which is tucked away inside the flower, sometimes protruding but in some cases always hidden. No greenhood provides a nectar reward to hard-working pollinating insects; all of them attract small male flies, either fungus gnats or mosquitoes, with a pseudo-pheromone, a chemical that mimics the 'come hither' scent of an interested female gnat or mosquito. When the amorously hopeful insect contacts the hinged labellum it snaps back, pinning the insect against the column, which contains both pollen and style. In its struggle the unfortunate gnat collects the sticky pollen, or delivers a bundle it's already carrying.

Two basic groups of greenhoods are recognised. The larger group is characterised by having upswept lateral sepals like the summer greenhood above, and the species featured in my last posting. Here are some more of this grouping.

Snail Orchid Linguella sp., Alligator Gorge, South Australia.
There are over 30 species of the little snail orchids, mostly in Western Australia;
unfortunately, at last count only five of them had been described!

Large Mountain Greenhood Pterostylis monticola, Namadgi National Park near Canberra.
Some 25 Australian species remain in Pterostylis under Jones' taxonomy. Here the labellum protrudes.

Nodding Greenhood Pterostylis nutans, Micalong Falls, New South Wales.
Not dozing, they always look like this!

Trim Greenhood Taurantha concinna, Callala, south coast New South Wales.
Again the labellum is obvious, protruding through the join of the two lateral sepals;
this angle is the sinus, and is used for identification.

In the other sub-group, the lateral sepals point downwards - ie they are deflexed. The leafy greenhoods are good examples of this group.

Common Leafy Greenhood Bunochilus longifolius, Callala, south coast New South Wales.
The highly mobile labellum is fully exposed and snaps shut to form a closed door when an insect enters.
It then has to struggle to get out, increasing the chances of it contacting the orchid's column.

Black-tip Greenhood Hymenochilus bicolor, Munghorn Gap NR, central western New South Wales.
These flowers are tiny. In the middle flower the fly-like labellum is exposed; in the other two it has
snapped shut, locking the insect inside.

Sikh's Whiskers (!) Oligochaetochilus boormanii Weddin Mtns NP, south-western slopes New South Wales.
Not all greenhoods are just green!

To end, a couple of more spectacular ones, albeit still in an understated way.

Jug Orchid Stamnorchis recurva, Twin Creek NR, Western Australia.
The only one of its genus, restricted to the west, and quite unmistakeable.

Unnamed Plumed Greenhood Plumatichilus sp. Alligator Gorge, South Australia.
Only four of the 14 known species of plumed greenhoods have been described;
they have in common these wonderful long yellow hairs along the labellum.

So, the greenhoods, subtle beauties. I have you've enjoyed them as much as I do.

BACK ON TUESDAY

March of the Orchids

I don't generally think of March as being a good time for orchids around here, but when I started to go through my records, I decided that I might be wrong. In this part of the world at least, it's not so much a time for colourful ones, but there are quite a few fascinating and beautiful orchids (sorry, tautology!) to be found in this first month of autumn. As I've mentioned before, Australia uses the Meteorological definition of the seasons, according to which autumn officially began on 1 March.

Several species of greenhoods can be seen now. A brief word on the somewhat fraught state of Australian orchid taxonomy to explain oddities relating to genus names. Traditionally all greenhoods - some 200 or so of them - were placed in the genus Pterostylis, and for probably the majority of people they still are. However, as part of their gargantuan task of re-examining nearly all the Australian orchid genera, David Jones and Mark Clements of the Australian Herbarium split Pterostylis into 16 genera, mostly based on already recognised sub-genera. Their work was thorough and largely based on biochemical criteria. Jones, recently retired, is widely regarded as the doyen of Australian orchid taxonomists and conservationists; Clements is also well-respected. Unfortunately they chose to publish in The Orchadian, the journal of the Australasian Native Orchid Society - which does not peer-review its articles. In large part due to this, much of their conclusions have not been accepted by other taxonomists.

However, the only comprehensive identification guide to Australian orchids is written by Jones - so you see our problem... Around here it's even trickier as he also authored an excellent Field Guide to the Orchids of the Australian Capital Territory, which we all rely on. All of which is a long-winded way of explaining why several of the species which follow have two genus names; given that my audience is international, I'll use the most widely-accepted names, with Jones' names in brackets. (The same issues arise with some other genera, but they are not relevant to this posting other than the last species featured.)

All these photos were taken in March, but not necessarily this year. Except where specified, the locations are all in the Australian Capital Territory.

Summer Greenhood Pterostylis (Diplodium) decurvum, Tidbinbilla Nature Reserve.

Dainty Greenhood Pterostylis (Diplodium) reflexum, Black Mountain, Canberra.
Below, part of a large colony.

Little Dumpies Pterostylis (Diplodium) truncatum, Black Mountain, Canberra.
I do like such quaint folk names, whose origins are now lost to us.

Blushing Tiny Greenhood Pterostylis (Speculantha) rubescens, Black Mountain, Canberra.

The rest of the featured orchids are not greenhoods, though there are certainly other greenhoods to be found. Dennis Wilson of The Nature of Robertson features a rare one here.

Large Midge Orchid Acianthus exsertus, Black Mountain, Canberra; above and below.
These were probably atypically early, but were well within March.
('Large' is relative, it's worth pointing out!)

Parson's Bands Eriochilus cucullatus,
above (Smith's Road near Angle Crossing) and below (Mongarlowe, New South Wales).
These delightful little orchids flower from late summer well into autumn; they range from rich pink to white.

Mountain Spiral Orchid Spiranthes alticola, Tidbinbilla Nature Reserve.
This a truly exquisite little orchid, with each flower being no more than 5mm long;
there can be dozens of them twisting up the stem.
This used to be regarded as one species, S. sinensis, found all the way to China, but Australian plants are now known as S. australis; the species illustrated is recently described by David Jones and is widely accepted.

Tiny Strand Orchid Bulbophyllyum (Adelopetalum) exiguum, Nowra, New South Wales.
Another delightful miniature, flowers only 5mm long, growing on logs and rocks in rainforest.The splitting of Bulbophyllum by Jones is also contentious

For a couple of other March orchids, see my recent post on my visit to Monga National Park.

BACK ON THURSDAY

Eurobodalla Regional Botanic Gardens; treasure at the coast

I suspect that the majority of Canberrans make the 150km journey across the edge of the Monaro Plains, through historic Braidwood and down the steep curves of forested Clyde Mountain to Batemans Bay at least once a year. Many own or have access to holiday homes of varying grandeur or simplicity up and down the coast; we don't, though we do spend three or four weekends a year there in general. 'The Bay' is a sprawling conurbation now, but there are still quiet little off-road settlements nearby. We have a flexible set of rituals while we're there, but one unbreakable rule is a visit to the delightful Eurobodalla Regional Botanic Gardens, 42 tranquil hectares of forest and open space dedicated to local native plants. 

As you will have by now divined, this is to be another in my occasional series on favourite botanic gardens, the most recent of which you can find here.

Prostanthera porcata, a threatened species from rugged slopes in the nearby Budawang NP, only described in 1984.
All plants in the gardens are local, which is defined here as the catchments of the Clyde, Deua and Tuross Rivers.

The story of the ERBG (if I may be so familiar) is above all one of community spirit and an unusually successful co-operative venture between community, local government and a state government department. In 1986, in a reversal of the usual way of doing things, a Friends group was formed to press for a local native botanic gardens. In 1988 the Eurobodalla Shire came on board, and NSW State Forests was convinced to lease the selected area - which had not been logged for 100 years - to the shire for use as a botanic gardens. A management committee was established to oversee the development. Most of the financial support comes from the shire, with the help of government grants and vigorous fund-raising by the Friends. 

As a result of being unlogged since the early 20th century, there are some big original eucalypts
in the forests of the Gardens.

The path has not been easy. A massive bushfire in January 1994 set development back a long way. In September 2010 a destructive storm brought down numerous trees, one of which crushed the new orchid house just prior to its scheduled opening. Some of the 7km of walking tracks are still closed following that event, awaiting the funds to clear them.

Nonetheless they are now a delight to visit. The first thing a visitor encounters is the cafe and visitors' centre, which come into view as we cross a little bridge over Pat's Creek, usually busy with birds.

The Chef's Cap Cafe is on the left, with the Wallace Herbarium on the right.
The tower provides cooling in summer by drawing up hot air from the buildings.

We always indulge in at least a coffee, if not lunch, at the cafe, attended invariably
by busily speculative Superb Fairy-wrens.

Superb Fairy-wren Malurus cyaneus male, moulting into his plain winter garb,
sharing a table at the Chef's Cap Cafe.

The garden beds emphasise plants suitable for home cultivation, as well as special theme plantings including dryland, wetland and sensory gardens. Plants propagated by the horticultural team but surplus to Gardens requirements are available for sale; some unusual species can be found on occasions. This Easter there's a big sale of these plants on - see here for more details.

Looking south from the Visitors' Centre.

Chef's Cap Correa Correa baeuerlenii, from which the cafe takes its name.
It is limited to about 150km of forests south from here.

Three quarters of the area is retained as original forest, with walking tracks winding through.

Wet sclerophyll forest along the gully of Deep Creek.

The tracks feature information signs, including on indigenous usage of local plants.

Discussion of indigenous use of Burrawang, the cycad Macrozamia communis, alongside the plant.

The ten hectares of cleared land were already cleared when the site was chosen; they are designed to encourage use, for picnics and family gatherings. Children are well-catered for.

Excellent playground, including large robust musical instruments, such as the 'harp' below, played by hitting with the metal pipes supplied and tied on!

All-weather picnic shelter.

Covered stage at amphitheatre, used for concerts.

Orchid house, built to replace the one destroyed in the 2010 storm.

Water features strongly throughout the gardens; water for the ponds is mostly drawn from Deep Creek.

Two of the rich, near natural-seeming artificial ponds.

From the bird hide looking out over extensive wetland at the north-western end of the Gardens.

And speaking of birds, they are of course another feature; here are just a couple that I've photographed here at different times.

Jacky Winter Microeca fascinans, an Australian robin, which hunts insects by 'perching and pouncing'.

Eastern Whipbirds Psophodes olivaceus are generally cryptic, but sometimes come out to feed on the lawns here.

Australian Wood Ducks Chenonetta jubata, appreciate both the ponds and the lawns where they graze.

Fan-tailed Cuckoos Cacomantis flabelliformis are spring and summer visitors, when their perpetual downward trills compete with the cicada chorus.

The gardens are well-marked on the left about five kilometres south of Batemans Bay on the Princes Highway. Bearing in mind that they're closed on Monday and Tuesday, make sure you put some time aside to visit next time you're down that way. Have a look here for some more information. Beware before you visit though - you'll be hooked too.

BACK MONDAY

Walking the Malabar Cliffs; the end of Lord Howe

As I have mentioned before, Lord Howe Island is a very special place. One very memorable walk is along the tops of the Malabar Cliffs at the north end of the main island. It's a bit of a climb, but only to a little over 200 metres above sea level, starting at Ned's Beach. From up here though - initially on Malabar Hill, then along the cliffs themselves and finally on Kim's Lookout at the western end (underneath the 'b' of Malabar in the map below) - the views are superb, south right along the island and north to the offshore islets.

Here are a few of those views.

Ned's Beach from Malabar Hill; the route up gives grand views out to the sea to the east.

Looking west along the cliffs.

View south from Malabar Hill; the settlement is to the right, Mounts Lidgbird and Gower loom in the distance.

Same view south, from Kim's Lookout, a couple of kilometres to the west.

Admiralty Islands from the Malabar Cliffs, looking north.

There is no doubt though that one of the highlights of the walk in summer is the floating parade of Red-tailed Tropicbirds Phaethon rubricauda that drift past, often displaying, sometimes in elegant courtship pairs. In these flights one bird drifts along while the other 'stands up' in the air, pushing so that it goes backwards, while both point their tails towards each other. At this time of year they nest on the cliff faces, in scrapes on the ground; here on Lord Howe is apparently the greatest breeding concentration in the world.

They range across the Pacific and Indian Oceans, but the places where we can enjoy them so readily from land are very limited. 

Sadly I didn't manage to catch a photo of the pair display, though we watched them entranced for ages.

These were the stars, but it would be unfair to ignore some of the other beautiful seabirds that soared along the cliffs.

Masked Booby Sula dactylatra; this is a big bird and their vertical plunges into the ocean from high up, chasing fish, are dramatic.

Sooty Tern, Onychoprion fuscatus;
they breed everywhere on the island in noisy restless colonies - the locals call them Wideawakes.

There are many excellent reasons to spend a week on Lord Howe; the Malabar Cliffs is one good one.

Roach Island from Malabar Cliffs.

BACK ON FRIDAY