Tag Archives: June

Winter at Mt Crawford Forest

To those who have visited the Mt Crawford area from Adelaide are usually left with an impression of an area that is noticeably colder and wetter.  I have had the pleasure of working in the area in the last couple of months and this impression has been reinforced, especially after getting drenched in heavy rain at my last visit.

IMG_20140620_093746

I took a picture with my mobile telephone showing the mist around us as we worked.  We were above the cloud base on the edge of a sandstone ridge.  It is easy to keep warm climbing up and down a slope like this.  We were removing feral pines that originated from the adjacent commercial pine plantations and you may be able to see one lying on the left of this image.

Diplodium robustum (12)

On a sunnier day earlier in the month I found a pair of flowers of Diplodium robustum, the Large or Common Shell Orchid.  These were on the ridge next to the Heysen Trail.  These, I am told, are taller than usual for the species and resemble a form that occurs in areas of mallee.

Diplodium robustum (7)

From the back the flowers are strongly striped with green and white.  These flowers were facing south.  Elsewhere there was a colony of about 300 plants with over 30 in flower or bud; the majority of these faced up the slope.  This appears to be a strategy to make it more likely for the flowers to be visited by the insect pollinators.  The pollinators are small insects called fungus gnats, which look like small mosquitoes and don’t eat at all in their adult stage.  Only the males are pollinators and they need to be large enough to trigger the labellum inside the hood of the orchid.

Diplodium robustum (4)

At the base of the two flowers I found these little rosette.  This, surprisingly, is the same species.  This plant will not flower this year; it is preparing to flower in a future year.  There is a smaller flower in the lower left of this picture that I did not notice until I started writing this post.  It looks like a bud almost finished forming.

Wurmbea latifolia (1)

Orchids are not the only interesting flowers.  This is one of my favourite lilies – Wurmbea latifolia ssp. vanessae (Broad-leaf Nancy).  This is a female plant with the dark ovaries seen in the middle of the flower.  The flowers are white with rich, hot pink colours near the centre.  This was the first one I found on the 7th of June.  By the 20th they were easy to find.  I am told that the peak of flowering is mid-July and that earlier flowering this year is a result of climate change.

I am looking forward to visiting the area next weekend and taking more photographs, if the wintery weather lets us.

Robust

Bunochilus viriosus – Adelaide Hills banded Greenhood or Tall Greenhood

This orchid used to be part of the Pterostylis family, and is commonly found with Urochilus sanguenea.  Like U. sanguenea, the plant will produce either a flowering stem or a leaf.  This genus is fairly common with species been found right across Australia.  Interestingly nearly every state has some species which are endemic to their state.

Its name viriosus means it is strong or robust.  It is found from the Mount Lofty Ranges across to Eyre Peninsula, and it can have some variation.  It flowers between June and early September.

Generally these plants are have several flowers on a single stem.  The plants with the most flowers tend to be older plants, and would have not flowered the previous year.  A feature of these flowers is a labellum which, upon touch, will move upwards trapping the pollinator.  While the pollinator struggles to free itself from the orchid, it will pollinate the flower.

Similarly to U. sanguenea, this orchid will also produce short and tall plants at the same site.  It has been observed for this species to reach over a foot high.

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The long and short of it

Urochilus sanguineus – Maroon Banded Greenhood

This species used to be listed as a Pterostylis, and is similar strucurally to the Bunochilus.  Often it is found with Bunochilus, but they have not been known to hybridize.  It has a labellum which is sensitive to touch.  The plant will either produce a flowering stem, or a sterile leaf.

Winter orchids: Linguella sp. Hills nana, Urochilus sanguineus

This species flowers from May to September, and can be found in most regions of South Australia, as well as Western Australia, Tasmania and Victoria.  It is believed that this plant may have originated from the west, as most Urochilus species are endemic to Western Australia.  South Australia only has this species.

Quite often I’ve seen a variety of heights of these orchids, on the same site, at the same time.  This is mainly due to the nutrients of the soil where the plants are growing.  The dwaft plants are called ‘depauperate’.  Another feature of these orchids is they can grow in clumps or as a single plant.

The flowers can be difficult to photograph as they are very darkly coloured.  However with the afternoon sun coming through them they are beautiful.  Taking photos of them with a flash makes these flowers almost look black, and hides the loveliness of these flowers.

I’ve provided two pictures below of this species, the first from the southern and the second from the northern Mt. Lofty Ranges to show there is really no difference despite location.  Overall the species only varies in height, and the flowers fade with age.

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Facing away

Diplodium sp.- Shell Orchid

In this post, I will be dealing with Diplodium robustum, Diplodium sp. Adelaide Hills, and the hybrid the occurs from both.  These plants flower between May and August.

The plants of this species will either have a small rosette of leaves or a flower with leaves growing from the stem.  These orchids tends to form large colonies, but only 10% will flower.  An interesting observation is that these flowers will grow facing the slope.  It could be that this is where the pollinator will come from.  The reason is not known, but it does make it hard to photograph the front of the flower.

All the flowers are facing in one direction.
Note the little rosettes around the plants

Another example of the flowers all facing the banking

The two parent species of Diplodium are determined by the length of the spike on the end of the dorsal sepal.  D. robustum has long spike and is pictured below, left.  D. sp. Adelaide Hills has a short spike and is pictured below, right.  The hybrids are more likely to finish flowering before their parent plants.

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Common in winter

Cyrtostylis robusta – Winter Gnat Orchid or Robust Gnat Orchid

This species is very similar to its sister Cyrtostylis reniformis.  The main difference is the flowering time with C. robusta flowering in winter and C. reniformis flowering in spring.  C. robusta tends to have smooth green leaves while C. reniformis has strongly veined aqua green leaves.  C. robusta has a larger flower that the other species.

Here is a small clip of some Cyrtostylis robusta.  There is a little fly on the labellum of the central flower.  However it is not a pollinator as the fly can not reach the pollen.  Just because an insect is on the flower does not automatically mean it is the pollinator.  The pollinator of these flowers is long-legged fungus gnats from the diptera family.

This species has a widespread distribution from Western Australia, through most of South Australia and into Victoria and Tasmania.  It grows in a variety of habitats, but prefers a sheltered area.  It can grow in exposed areas, but these plants do not tend to flower.  It is a reasonably common orchid.

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Up now…

Just a couple of pictures of leaves that are up at the moment.

Pterostylis pedunculata
Maroon-hood

Arachnorchis tentaculata
King spider orchid

Nemacianthus caudatus
Mayfly Orchid

Pyrorchis nigricans
Black Fire Orchid

Pyrorchis nigricans
Black Fire Orchid
Picture shows the stripes on the underside of the leaf

Microtis sp.
Onion orchid
The flower of these plants grows inside the tubular leaf, and breaks out of it for flowering

This miniature orchid has finished flowering.

Corunastylis sp. Adelaide Hills
Common Midge Orchid

Hey, you aren’t an orchid…
Behind are some Pterostylis pedunculata leaves (the dark green).

The little hardy one

Acianthus pusillus – Mosquito Orchid

This orchid is so common, many orchid enthusiasts overlook it when on an orchid excursion.  It is small, difficult to photograph, and as it is very close to the ground, many don’t think it is worth the effort getting all the way down to photograph it.  It is a tough and hardy little plant.

Nemacianthus caudatus is a similar species but has longer sepals.

It is very small.  On a healthy flower stem of just over 10cm, it may have over 10 flowers.  The flowers are less than half a centimetre high.  Coupled with its size, and dark colour it is very difficult to photograph.  I’ve observed that photos taken with a flash make the stem and flowers appear a dark brown/red colour but without a flash it looks more purple.  It has a distinctive heart-shaped leaf which is purple underneath.  Its sister is Nemacianthus caudatus (Mayfly Orchid), which flowers after the Mosquito Orchid.

It does have a long flowering time from April to July.  This occurs if they are not pollinated.  The little pollinator is a small fly, which is difficult to find even on a large colony of plants.  However on some of these plants we had at home I notices some of these pollinators.

Like most orchids, the little mosquito orchid tends to grow in shady areas.  This orchid is often found near the bases of trees, in a moist little corner.  It does have a tendency to grow in colonies.

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