Journal Number 111
February 2009

AUSTRALIAN NOTES
By David McConachie

31st August Bushwalk Report - Harvey Bay
By Graham Corbin
Reprinted from Kalhari Sep. 2008 pp31-36

This month had a change of venue from the advertised bushwalk. Five KABI members joined 23 Harvey Bay OS, Childers OS and Maryborough OS members for a bushwalk in the Harvey Bay area. While this was quite a drive with the southside members leaving home shortly after 5am, it was well worth the early start with some very beautiful and unusual orchids found in flower.

The fun started at the meeting place on the highway near Maroom. Those who got there early immediately found numerous Microtis parviflora growing in the roadside drain with virtually all in bud and quite a few with open flowers. Those new to our local native orchids were surprised that these were indeed orchids and the tiny size of the flowers, too small to appreciate with the naked eye being only 2 to 3mm wide.

With the success of orchids next to the cars, off we charged into the low heath and were soon rewarded with more plenty more flowering Microtis parviflora. Nearby, we found numerous Thelymitra all in flower but with the flowers still closed. These orchids, commonly known as sun orchids, only open their flowers on warm sunny days and at 8:30am, it was just too early to expect the flowers to be open. A single flower of Caladenia fuscata was found, but this flower was very old and quite damaged.

A bit more searching revealed a Cryptostylis subulata in flower. This interesting orchid commonly known as the tongue orchid had 3 open flowers with 3 buds yet to open. This is one of our few evergreen terrestrials with a single gum-leaf like vertical leaf. There were dozens of plants in the area as shown by the abundance of the leaves, but only one plant was in flower.

Interestingly, unlike most orchids, the flower faces the flower stem, so most people new to this species study the back of the flower rather than the face. By this stage, all those attending had arrived, so with the success of our 'unofficial' orchid stop, we moved on to the first official stop with the promise of yet more orchids.

We next walked through an area of light tree cover with a sparse grassy understorey. We soon found numerous examples of fresh Caladenia fuscata. This beautiful species is one of the smaller Caladenia and can be identified by the pink flower colouration with red stripes on the column and labellum and the labellum tightly embracing the column.

Nearby, we found two Dipodium variegatum in flower. One of a number of Dipodium species in Australia, this species can be instantly identified by the purple spotting extended to the pedicel.

Further down the track were a few flowers of Glossodia minor, a lovely blue purple flower. There are two species of Glossodia, both restricted to Australia and both found in the area, the other being G. major. Both have quite similar flowers, but can be separated by the labellum, with G. minor having a small rounded labellum and G. major having a much larger pointed labellum.

Unfortunately, none of these flowers were fresh will all showing some degree of damage but were still very nice to see. The flowers did show interesting variations in the labellum basal callus colour. This callus is usually purple with a yellow base, but one flower had an almost totally yellow callus. Very interesting. The walk back to the car revealed hundreds of Pterostylis rosettes, possibly Pterostylis baptistii from the leaf size and shape. Many rosettes showed spent flowers, but none had identifiable flowers.

Next, the group moved on for a tour of the thriving town of Maaroom, a typical blink and brief stop at the district hall to search for Spiranthes sinensis growing in the lawn. These usually flower from November to April and we could find no sign of their rosettes, maybe too early for them to emerge. We did however find a thriving colony of Microtis parviflora growing and flowering in the lawn.

A short drive away, we found our first Diuris alba. This beautiful white donkey orchid with purple markings proved to be very difficult to photograph with its tall slender stem swaying wildly in the wind. This was only the first of this orchid we found with dozens more found along the side of the road. This orchid seemed to prefer the wet areas in drains and low lying areas and was quite common in these areas.

A shout from nearby revealed yet another orchid, this time a Thelymitra fully open. Nearby where yet more of this orchid which were later identified as Thelymitra pauciflora. Large numbers of this orchid were found all down the road. This beautiful orchid was indeed very common in this area. Further down the road, another very similar but subtly different orchid was photographed. While it looks identical at first glace, it is a different species, Thelymitra nuda. These two species are virtually identical but can be separated by T. nuda having larger flowers and straight column arms while T. pauciflora has smaller flowers with bent column arms.

Continuing walking down the road revealed large numbers of another similar looking Thelymitra, this time Thelymitra purpurata. The beautiful blue flowers of this orchid contrast nicely with the yellow tip to its column.

Continuing down the road revealed a large number of Prasophyllum elatum growing in a low lying wet area. These large orchids have flower spikes over 1m tall with over 50 flowers on a spike. These orchids generally prefer swampy areas and these orchids obviously had found a suitable wet area.

By this time, time was running very short, so we reluctantly set off for our next stop. Here we found hundreds of Dendrobium tetragonum growing on the Melaleuca trees. We unfortunately did not find any of these orchids in flower, but we found plenty of spent flowers no more than a couple of weeks old. It was quite interesting that these orchids showed a distinct preference for the Melaleuca trees as we found none growing on any of the other trees in the area.

We then moved onto our lunch stop were we enjoyed lunch together discussing the orchids we had seen. We all agreed that the day had been a wonderful success both with the large number of members from the four different societies who attended and the large number of interesting orchids seen. Hopefully, the next Orchid walk in the area won't be too far away.