Caladenia exstans - Pointing Spider Orchid

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Caladenia exstans  -  Pointing Spider Orchid

A coastal to near coastal orchid of restricted distribution between the Mt Merivale/Cape Le Grand region (east of Esperance), and Israelite Bay, preferring moist acid sandy loams around granite outcrops or Yate Swamps (Euc. occidentalis), where in the latter it grows on the slightly raised and better drained areas. Flowering is normally from September to early November.

Although this orchid can reach almost ½ metre in height, its wispy nature and habitat blending colouration makes it difficult to see, as the eye is usually looking for smaller plants closer to the ground. As a result, I tend to spot this orchid from a short distance, rather than when standing nearby.

From my observations, the flowering of Caladenia exstans is quite erratic, occurring one year then going several years without. It seems to be more common after bushfires or at least when influenced by the smoke.

Apart from C. integra from the Albany/Perth region, C. exstans is the only other WA green spider orchid to have a smooth edged labellum, plus only occurring in a restricted zone east of Esperance, it is unlikely to be confused with another species. The common name of Pointing Spider Orchid, refers to the tip of the labellum, which remains extended (pointing), unlike most spider orchids that have a furled tip.

Caladenia voigtii - Mohawk Spider Orchid

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Caladenia voigtii  -   Mohawk Spider Orchid

To date this species has only been recorded in a broad band of mallee country from around Balladonia to Salmon Gums and then onto the Lake King district, where numbering from a few individuals, to spreading open colonies where collectively common.

Personally, I have not encountered this orchid near saltlakes (recorded habitat), although they have been in the general vicinity, but in deep (acid) sandy soils with mallee heath/woodland, it is also found around granite outcrops, where it can grow to 20 cm (8”) in height. It is noted being in flower from August to October, but with adequate rainfall and mild conditions will continue well into November.

In habitat it is easily confused with the more common Short-sepaled Spider Orchid, Caladenia brevisura, but the labellum of C. voigtii has a taller and more dense row of red-tipped calli, plus lacks the clubbed sepals of C. brevisura. It tends to flower later too.

Caladenia roei overlaps C. voigtii in the western portion of its distribution, but that species has spreading petals and sepals in a crucifix shape, plus shorter deep purple calli on its labellum.

Caladenia voigtii is named after Don Voigt, an Esperance orchid enthusiast who discovered this species near Salmon Gums (north of Esperance) in 1977.

Caladenia cruscula - Reclining Spider-orchid

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Caladenia cruscula - Reclining Spider-orchid

This Spider Orchid is mainly found around the large saltlake conglomeration 75 km (45 miles) North and NE of Esperance, where it grows in a fine sand/clay loam around the playa lakes. The preferred habitat from the ones observed is on gentle slopes 50 to 100 metres/yards from the open saltlake zone. A couple of small groups were seen about 30 metres away, but these were exceptions. Also they were growing in well-drained open ground, or under tall Melaleuca and mallee Eucalyptus, where ground cover was sparse. However all Caladenia cruscula orchids were sheltered from the normally windy open lake environment behind at least one row of bushy 4-5 metre (12’-15’) tall shrubs and/or mallee eucalypts.

Caladenia cruscula is very similar in appearance to Caladenia longicauda subsp. rigidula, which also grows in the region, but around granite outcrops and inland mallee winter-wet environments. So besides different habitats, they also differ in the length of the lateral sepals and petals that are shorter with C. cruscula, being to 4 and 5 cm (nearly 2”) in length, whereas C. longicauda subsp. rigidula are a good 1 cm (1/2”) longer. Possibly due to their shorter length, the sepals and petals are also quite stiff and less flexible. However the most dissimilar features are centred on the labellum, with C. cruscula being shorter in length with less calli past the bend, plus the vertical fringe is shorter. And last but not least, the reverse side of the leaf is mottled red in the lower portion. These variations can be viewed as a direct comparison in the Caladenia longicauda subsp. rigidula post (see lower right-hand column).

Around the larger saltlakes of the Truslove Road district, this orchid is reasonably common and quite widespread, occurring as single individuals or small groups in extended colonies. However they appear to be very habitat specific, which may reflect the drainage pattern of these areas, where rainfall slowly seeps down the slope on a probable clay or limestone substrate. Flowering is recorded from August to October.

Caladenia longicauda subsp. rigidula - Inland Spider Orchid

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Caladenia longicauda subsp. rigidula - Inland Spider Orchid

This spider orchid is known mainly from granite outcrops to the north of Esperance, but with photographs alone it is very difficult to distinguish from other Caladenia longicauda subspecies. However the smaller size (11 cm or 4.25” across) and location is what gives it away. When first sighted it appeared to be a large form of Caladenia vulgata the Common Spider Orchid of which one was growing nearby, but the red fringe on the labellum immediately highlighted the difference.

Another similar looking orchid Caladenia cruscula also occurs in the area (Kau Rock to the Mt Ney region), but is smaller again (5 cm or 2” across) and only known from sandy rises around saltlakes. Two Caladenia longicauda subsp. rigidula plants were observed 65 km (40 miles) NE of Esperance, one under shrubs in a sandy loam over granite and the other, several hundred metres away under low mallee eucalypts in a sandy loam over gravel (in turn over granite).

The height of these orchids also separated them from other Caladenia longicauda subspecies, which were around 15 cm or 6” as compared to more than twice that height with other local (more coastal) subspecies. Also the sepals are held more stiffly, being less pendulous than other subspecies. It apparently flowers from August to early October.

It will probably be gathered from the photos above, the orchid with the straight labellum is still developing, whilst the mature plant has the recurved labellum.

Update Feb 2011
Two photographs added that were taken in October at Mt. Heywood, which is 20 km further north from where the others were taken and sited in the mallee region.

Caladenia cairnsiana - Zebra Orchid

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Caladenia cairnsiana - Zebra Orchid

A widespread orchid growing on a variety of soil types, with those photographed above in sand over granite and on gravel. This species is mainly coastal or near coastal, whereas a similar looking species the Dwarf Zebra Orchid - Caladenia pachychila has a more inland distribution, however they do overlap to the north of Esperance. Caladenia cairnsiana tends to be a little taller (to 30 cm or 12") and has more pronounced red stripes on the labellum. Also the lateral sepals and petals hug the ovary, whereas with Caladenia pachychila they are more spreading. The labellum is held more vertically with C. cairnsiana, whilst C. pachychila is more horizontal. And as the name of the Dwarf Zebra Orchid, Caladenia pachychila indicates, the callus at the end of the labellum is thicker lipped compared with the similarly placed callus on Caladenia cairnsiana.

As with a number of terrestrial orchids these species are apparently pollinated by small wasps that are attracted to the flowers by their release of pheromones similar to sexually receptive female wasps. The thick black calli in the throat of these orchids would no doubt appear to the male wasp like the female and upon landing in order to mate, would brush against the anther to carry the pollen to the next orchid flower it is deceived into alighting.

The flowering period of Caladenia cairnsiana is recorded from August to November, but this would depend on location and seasonal rainfall as these factors can vary flowering times considerably.

Caladenia arrecta - Reaching Spider Orchid

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Caladenia arrecta - Reaching Spider Orchid

A recently described (2001) Spider Orchid and considerably more common in the SW of the State, particularly around Busselton. In the Esperance region it is mainly found immediately to the north of the town and further to the west, although it is nowhere common and has a Priority Four rating (rare but not endangered). The orchids above were discovered by a couple of flora enthusiast (Lyn and Eric) from Tasmania who kindly advised me of their presence, which was not far from Munglinup (95 km or 60 miles west of Esperance). The habitat was a roadside reserve with a gravel soil, on which grew scattered low mallee eucalypts and heath that had recently been burnt. There were approximately 20 Reaching Spider Orchids sited on the outer edge of the burnt eucalypts and usually in small hollows where rainwater would collect before slowly draining away.

Caladenia arrecta is quite a chunky orchid possibly reflecting the densely packed glandular cells on the outer portions of the sepals and petals. The overall flower depth can be as much as 8 cm (over 3"), although those above were closer to 5 cm or 2", nevertheless as most had two flowers per plant, they made a memorable display. Flowering time is recorded from August to October, although the above had obviously been in bloom during July, however there were still a number yet to flower and others that had just started, so August/September would certainly be the best time to observe these particular orchids.

Caladenia attingens subsp. gracillima - Small Mantis Orchid

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Caladenia attingens subsp. gracillima - Small Mantis Orchid

Reported as being common and widespread, but I have not found it so to the NE of Esperance, which may just reflect me being in the wrong places at the right time. This one was encountered near shrubs in a shallow clay/sand soil over granite, where rainfall would drain on its way to the lower exposed rock and so keep the root zone reasonably moist. The Small Mantis Orchid is also found near watercourses and saltlakes.

Readily recognised by the green broadly toothed labellum, which is easily spotted against the red soil and grey leaf-litter of granite surrounds. Flowering time is recorded as August and September, but in the drier areas I would imagine this could vary a little depending on the region's low and irregular rainfall.

Update 3/10/10

Two photos added (leaf and profile), taken around the edge of a saltlake in a sandy loam over granite, to the SE of Mt Ridley (mallee region NE of Esperance). Scattered individuals facing east, mostly near the granite edge overlooking the playa lake during early October. Despite fresh flowers, the leaves had shrivelled on all but one, which was sheltered by taller vegetation. The leaf reverse was strongly mottled red/green over most of its length.

Caladenia microchila - Western Wispy Spider Orchid

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Caladenia microchila - Western Wispy Spider Orchid

This orchid is distinguished from others by its tiny labellum, which is apparently the smallest amongst WA spider orchids and possibly Australia also. The width when flattened is only 4-5 mm (less than 1/4") and when compared to my fingers above, which are approximately 20 mm (7/8") wide, the small size of the labellum is immediately apparent.

Other characteristics of this orchid are the petals, which are held above the horizontal and the slender sepals and petals with their long wispy glad covered tips. Although known for its widespread preference for growing on limestone, in the mallee to the NE of Esperance it is more commonly found on a sandy clay loam immediately over granite. Flowering occurs in August and September, extending into October when rainfall is late and mild conditions prevail.