Thelymitra petrophila - Granite Sun Orchid

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Thelymitra petrophila - Granite Sun Orchid

This attractive species is quite common in soil pockets on and around granite outcrops, favouring the heavier reddish brown loams that frequent these environments. Locally, it can also be found in a similar soil over limestone where light seepage gravitates through it to a lower-lying granite environment.

Although this orchid enjoys moist soils, it seems to dislike humid conditions, preferring the drier inland by staying well away from the southwest of the State or coastal regions either side of Perth. The extensive area where it does occur is from Kalbarri to the Nullarbor, plus the southeastern coastal area extending inland to the northwest of Kalgoorlie.

Most plants mature at 30 cm (12”) in height, although some can reach twice that size when they grow through low vegetation. They seldom develop in exposed locations, but probably due to browsing animals like kangaroos, tend to frequent open shrubby copses.

There are up to ten flowers to 2 cm (3/4”) diameter, which open readily on warm sunny days between August and November. Their colour varies to include pink, purple and blue, with the latter being the norm around Esperance.

Coastal Sun Orchid - Thelymitra granitora

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Coastal Sun Orchid - Thelymitra granitora

A stocky orchid to around 30 cm (12") in height, which are self-pollinating and will only open on sunny, warm, humid days. Although its botanical name refers to its preference for a granite habitat, it can also be encountered on and around flood plains, particularly at the base of trees. It is usually found in condensed colonies of up to a dozen plants on granite outcrops, or in ones and twos elsewhere.

It is an impressive looking orchid with a short thick stem and a large fleshy channelled (curved) leaf, giving rise to great expectations as to a spectacular flower, but alas it seldom blooms. The flowers are not unattractive when encountered, usually being to 3 cm (around 1") diameter and pale blue, with the brushes either side of the column being held high near the yellow column summit. Flowering period is short being only during September and October.

Blue Lady Orchid - Thelymitra crinita

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Blue Lady Orchid - Thelymitra crinita

One of my favourite orchids due to the amazing blue color of the flowers. The 30-40 mm diameter flowers (around 11/2") have intense richness and depth, plus bloom freely on sunny days, so the 600 mm (2') tall blue lady always puts on a good show. Besides the beautiful flowers it also has a large impressive leaf (commonly around 100 mm or 4" in height by 50 mm or 2" in width), which presents long before the flowering stem, but at least you know one is on the way.

It is a widespread orchid, but usually only occurring in small-scattered colonies. It favours moist soils in sandy heath, but not wet sites, preferring to grow near seepage zones, flat (non-flooding) low-lying areas, around ephemeral swamps (often just above the Agonis vegetation), or granite outcrops. It does not need a bushfire to stimulate flowering, but can be smothered by other vegetation, therefore periodic burns to restrict taller growing shrubs would be an advantage. It can flower as early as September or as late as November, but tends to be more common during October.

Thelymitra vulgaris - Slender Sun Orchid

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Thelymitra vulgaris - Slender Sun Orchid

This species is mainly a coastal or near coastal orchid, occurring from Esperance to north of Perth.  It grows to 40 cm (16") in height and produces between 2 - 10 blue, mauve or even white flowers to 2.5 cm (1") diameter, which bloom (depending on local weather conditions) anytime from September to December.  The flowers are self-pollinating and often do not open fully, requiring warm sunny days to do so.

The Slender Sun Orchid is quite a common species of acid sandy heath and locally can be found in moist soils around ephemeral swamps and seepage zones. Bushfires aid these orchids by clearing larger plants that would otherwise smother them, but they can still be found in unburnt areas providing it has not become too overgrown.

Lemon-scented Sun Orchid Hybrid - Thelymitra antennifera X

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Lemon-scented Sun Orchid Hybrid - Thelymitra antennifera X

This Sun Orchid hybrid is a bit of a mystery as to who its parents are. It seems likely due to the large column wings, that one is Thelymitra antennifera, the Lemon-scented Sun Orchid, which is very common in the area, and the other being one of the blue colored species (in order to produce the pink petals). There are several blue flowering sun orchids in the region, but the hybrid flower is much larger than most of them, being at least 40 mm (nearly 2") diameter. There is only one species (presuming the hybrid flower size is related to the parent orchids flower size) that is found nearby, and that is Thelymitra macrophylla the Scented Sun Orchid. Here: Orchids - Sun - Scented

There were around a dozen plants (most had finished flowering), growing within a few metres of each other, at the base of a sandy rise on the edge of a saltlake, but behind tall bushy Melaleuca species. So a protected and probably moist position with a sandy surface, shallowly overlying a heavier clay substrate (interestingly a habitat also favoured by T. macrophylla).

The photographs above were taken in mid October, the aftermath of a summer bushfire. So the main flowering period would be September to early October. This is compatible to the flowering times of the suggested parent orchids. I have returned to the site in following years but have not encountered the hybrid again. Whether this is due to a lack of rejuvenating bushfires, rapidly regenerating (smothering) vegetation or for some other reason, I cannot say.

Lemon-scented Sun Orchid - Thelymitra antennifera

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Lemon-scented Sun Orchid - Thelymitra antennifera

Due to the two large upright lobes at the rear of the column, this sun orchid is also known as Rabbit's Ears. Personally I think it also resembles a cute little dog, but whatever you think, this orchid has a lot going for it. It would be the most common of the WA Sun Orchids, growing in a variety of moist habitats and although doing particularly well after summer bushfires, it can still be commonly found in low vegetation and along walking tracks in unburnt areas.

Apart from the cute little faces, the flower is also heavily lemon-scented, presumably to attract insect pollinators. This is further aided by large yellow flowers (to 30 mm, over 1" diameter), that open freely and can be seen in full bloom even on cloudy days.

Growing to a height of around 250 mm (10"), the flowering stem is kinked at the nodes and on casual observation looks very similar to another orchid, Thelymitra flexuosa, the Twisted Sun Orchid, which also has yellow flowers and grows in similar habitats (for further details see 'Orchids - Sun - Twisted').

In some areas it can apparently flower as early as July, but in the Esperance region September and October would be more the norm.

Twisted Sun Orchid - Thelymitra flexuosa

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Twisted Sun Orchid - Thelymitra flexuosa

A reasonably common orchid of seepage zones, around ephemeral swamps and granite outcrops. The flowers are often not closely examined, as they need a calm sunny humid day to open, if these conditions do not occur, they may not open at all and self-pollinate. It derives its name from the zigzag bend in the stem, which you might think would make it highly distinctive, but another even more common orchid, Thelymitra antennifera, the Lemon-scented Sun Orchid also has a zigzag stem, its flowers are also yellow and it occupies similar habitats at similar times, so the Twisted Sun Orchid with usually closed flowers, is often mistaken for the more common orchid.

The flowers of T. flexuosa and T. antennifera are quite distinct. T. flexuosa has smaller flowers to only 15 mm (5/8") diameter, around half the size of the other orchid. The column of each species is noticeably different with T. antennifera having large ear-like lobes, whilst T. flexuosa has none, so no confusion if flowers are sighted. Flowering time for the smaller flowering Twisted Sun Orchid is from August to October.


Update 11/10/08

Photo of the closed flowers added to show the yellow exterior, as compared to the similar looking orchid T. antennifera that has a pink/red exterior.

Azure Sun Orchid - Thelymitra occidentalis

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Azure Sun Orchid - Thelymitra occidentalis

This sun orchid was previously known as Thelymitra azurea, as it has striking purple/blue flowers matching the common name of Azure Sun Orchid. Commonly found in low-lying heath around winter-wet swamps and seepage zones, but can also be encountered on sandy rises near saltlakes. It flowers particularly well after a summer bushfire, but will still do so without, providing the area has not become overgrown.

Apart from the color, the most distinctive feature of this orchid is the raised yellow lobes on the rear of the column. It stands around 400 mm (1' 4") in height, with flowers to 30 mm or a little over one inch diameter; these are produced on warm sunny days. Flowering is from late September, but more usually during October and November.

Leopard Orchid - Thelymitra benthamiana

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Leopard Orchid - Thelymitra benthamiana

A very impressive chunky orchid growing to 500 mm (over 1' 6"), with bright yellow and brown spotted flowers that can expand to 40 mm (over 11/2") diameter. Even the leaf is impressive growing to over 150 mm (6") in height by 50 mm (2") wide and supported on a winged stem.

Not a common orchid around Esperance, but can be found within Yate swamps, in the lightly vegetated, better drained edge of light seepage zones (often the outer edge of Agonis thickets where they peter out under the Yate trees, Eucalyptus occidentalis). They do very well after a summer bushfire, but will continue to flower providing they are not smothered by larger vegetation.

Flowering usually begins in September and finishes during November.

Southern Curly-locks Sun Orchid - Thelymitra uliginosa

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Southern Curly-locks Sun Orchid - Thelymitra uliginosa

Previously placed with Thelymitra spiralis, but now separated into different species by Dr Jeanes, although formal recognition is still in manuscript form. This species however is detailed in the publication 'Orchids of Western Australia' by Andrew Brown et.al. Apparently it differs from T. spiralis by its smaller flowers (3 cm or little over 1" diameter), which have a 'deep blue-mauve coloration and prominent stripes.' Flowering during August and September.

The curly-locks name refers to the shape of the basal leaf that is curled like a spring. Not a common orchid in the Esperance region, but apparently widespread further west. I discovered the one above on a broken limestone slope where seepage flowed during wet periods, but it can also be found in other moist sites, preferring the heavier soils around granite outcrops and swampy winter wet zones.

Tiger Orchid - Thelymitra tigrina

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Tiger Orchid - Thelymitra tigrina

I have only encountered a single colony of this orchid in the Esperance region and that is on a gentle slope just below Banksia heath (acid peaty/sand), on a lightly slashed track with sub-surface seepage. There are several dozen plants confined to a thirty metre (100 feet) section, but as this habitat type also occurs elsewhere, it is likely this orchid would also.

There has not been a bushfire in this area for a number of years, but the annual slashing would keep the habitat open and so reproducing at least that aspect of a fire. The habitat is dominated by a vertical, round stemmed sedge of similar dimensions to that of the Tiger Orchid, which means the orchid is largely invisible until it flowers. Fortunately for me these orchids flower reasonably freely, which apparently they don't in other regions in the SW of the State, so at least their flowers of around 10 mm diameter (3/8") and being bright yellow are reasonably obvious, but in more overgrown vegetation (presumably if they would still flower) they may not be.

The Tiger Orchid is a late flowering species, blooming from November to January, with most of my colony during the month of December.