24/09/2018

Today is a public holiday to celebrate the Queens Birthday in WA, however Debbie has to start her overnight shift at 2.00pm, so my dilema is what to do on a lonely afternoon when the weather is fine. 

Go orchid hunting of course!! 

Location ?

Dempster Head it is, as my last visit was back in late July. (Mud Map SE34 )

Leaving the car at the Rotary Lookout I venture towards Dempster Heads looking into the scrub alongside the granite. I then take one of the tracks made by mountain bikers, which are now banned from the Nature Reserve. My first find is a small Spectacled donkey orchid (Diuris conspicillata) which is only found around coastal granite outcrops in the Esperance area. They flower during August and September. The common name refers to the fact that the dark patches on the labellum lateral lobes are toward the centre rather than the edge, as is the case with all other donkey orchids. The scientific name, Conspicillata also means spectacled. A pair was found nearby looking like they are nearing the end of their season. So lucky to have found these to document for the first time.

The flowers have broad, ear-like petals, a short, relatively wide dorsal sepal and hanging, usually crossed lateral sepals.

Diuris conspicillata was first formally described in 1991

So I move back towards an area that I had previously found orchids from the Pterostylis genus, hoping that there may be some late bloomers still in flower. I luckily find one small snail orchid still flowering. I have identified this one as the Eastern granite snail orchid (Pterostylis voigtii) which is found Esperance to Israelite Bay flowering July to early September. Given the dates it is a wonder I still found one in flower.

Standing only 50mm in height.

Both orchids found so far are ones limited in range to the Esperance area, which is very special. Moving back towards the mountain bike tracks I stumble across another Esperance orchid. The Esperance king spider orchid (Caladenia decora) which does occur over a much larger area, from Fitzgerald River National Park to Cape Arid National Park during August to October.

Single, erect, linear, hairy leaf, 9–22 cm long and 6–10 mm wide.

Dark red-tipped labellum

Flower height 60 – 150mm Flower width 50 – 100mm

One hand behind it’s back

Up to three red, yellow and green flowers

Backswept, usually elevated petals

Fringe of narrow teeth up to 9 mm long but suddenly decreasing in length about half-way towards the tip of the labellum.

Prominently clubbed sepals

As one of the largest spider orchids in WA it makes an impressive sight. Especially when compared to the next orchid found. I have moved over to the port side of the reserve past the Water Authority tanks. Here I found a small group of  leek orchids of the prasophyllum genus. They appear to be the Laughing leek orchid (Prasophyllum macrostachyum) due to the smaller size of the flowers lateral sepals. These guys flower September to January within 100km of the coast from Dongara to Cape le Grande. This is a new find for me as we usually find the very similar Little laughing leek orchid.

Small flowers, widely spaced

Full plant shot with aging tubular leaf

Flowers inverted. Lateral sepals point upwards

I now make my way back towards the Rotary Lookout, but detour below the Water Authority tanks. This was a fortuitous choice as I stumbled across a couple of Esperance white spider orchids (Caladenia longicauda subsp. crassa). These large white spider orchids flower during September and October from Bremer Bay to Cape Arid National Park.

Broad base to lateral seapls

Erect dorsal sepal

Sepals up to 110mm in length

Single, hairy leaf, 120 – 250mm in length, 8 – 140mm in width

Four or more rows of red calli

Moderately long marginal teeth to the labellum

Nearly 5.30 in the afternoon, so I had better make tracks home. Was a very successful hunt around Dempster Head Nature Reserve, with 5 orchid species from 4 different genus found.