Monthly Archives: June 2012

Helmets

Corysanthes diemenica – Veined Helmet Orchid

Upon first inspection, it looks like some moss where some gum-nuts have fallen.  However, it turns out that the gum-nuts are these little helmet orchids.  These orchids tend to grow in moist areas, and will often be found near the base of large trees.

It is interesting to note the name of this species, “diemenica” was derived from Van Diemen’s Land, Tasmania’s old name from its early colonial days.  This was where this species was first discovered.  Australia has over 20 species from the Corysanthes family, with the rest being found in surrounding countries including New Zealand, New Guinea and up into South East Asia.

Note the small point on the apex of the leaf

This species flowers between July and August.  Its flowers are small, about the size of you  thumb fingernail.  They tend to colonize, and not just one species will be found in one patch.

An interesting feature on these orchids is a small point on the apex of the leaf.  This feature has not been recorded in the plants descriptions, but it was present in all our photographs.

Know Them

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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.

Know Them

Know Them

Know Them introduces you to a South Australia orchid every couple of weeks.  So far two posts have been published which are listed below.

Published

Acianthus pusillus – Mosquito Orchid

The little hardy one
This is the orchid that is so common, that many orchid enthusiast will overlook it when on an orchid excursion.  It is small, difficult to photograph, and as it is very close to the ground, many…

Leporella fimbriata – Fringed Hare Orchid

Sand lover
This common orchid is found in sandy soils flowering mainly from March to May.  However it can grow in gravelly soils, but requires fire to encourage flowering, where as colonies will flower readily…

Coming

Yet to come are the orchids pictured below, and more.  Please subscribe to receive updates when an new orchid is posted.

                                                                                         

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.

Know Them

Parts of an Orchid

It is good to know the different parts of an orchid.  The flowers have six main parts.

  • Three sepals
  • Two petals
  • One labellum (meaning tongue)

Another important feature of the orchid is the column.  This is where the pollen is found.  The ovary behind the flower will swell after pollination, and the seed develops in it.

Orchid have a feature called a bract.  This is like a leaf, but in botany is not considered one.  In identification of some orchids, particularly Thelymirtra or Sun Orchid, the number of bracts can assist in orchid identification.

Images from: Start with the Leaves: A simple guide to common orchids and lilies of the Adelaide Hills by Robert Lawrence © 2011
Used with kind permission from the author.