Journal Number 92
September 2004

AUSTRALIAN NOTES

Alpine Orchids and Fire
By Dick Thomson.
Australian Native Orchid Society (Vic.) Bulletin Vol. 36, 8 March 2004.

Over the last decade, Marion and I have been studying the summer flowering alpine orchids around Kiandra. The area was extensively burnt in the fires of January 2003.

While it was good to see the orchids that survived the fire, the spectacular mass-flowering of other species such as Yellow Billy Buttons (Craspedia sp.) and Bulbine Lillies (Bulbine glauca), the Pink Trigger Plants (Stylidium graminifolium) and the White Prickly Star-Wart (Stellaria pungens) was a sight to behold. But the most beautiful were the half metre high pale mauve mist of the Pale Vanilla Lily (Arthropodium milleflorum) rising up the hillside among the black trunks.

Thelymitra cyanea produced strong, mostly multiple, flowers on the majority of remaining
plants. It appears that at least 95% of the plants had been destroyed when the sphagnum
bogs were burnt.

Thelymitra nuda (alpine form) flowered in normal numbers. It is interesting to note that this orchid produced no flowers and very few leaves last year, in the drought that preceded the fire, and had its flowers and some leaves destroyed by a heavy snows falls in the previous season. Thelymitra decora appeared to have flowered as normal, although the small numbers make it difficult to be confident in this prediction.

Caladenia alpina flowered in normal numbers and there appeared to be a much heavier seed set. Pterostylis monticola was much reduced in numbers with only a few flowers. Plants seemed to be distressed by the extra sunlight they were receiving.

Chiloglottis valida was severely reduced. Plants that remained were close to the edges of rocks or in the compacted soil of walking tracks. No flowers were seen. Pterostylis cycnocephala (alpine form) seems to have been much reduced, although the very dense regrowth of grasses made it difficult to locate plants.

Dipodium roseum was not found flowering in lower altitude areas that were burnt. Gastrodia procera and G. sesamoides were not seen flowering in the burnt areas but flowered in non-burnt areas - sometimes in unburned patches within the burned area.

Diuris monticola seemed to be flowering in average numbers. The alpine Prasophyllums were flowering in their usual numbers. In a heavily burnt area we also located a dozen plants of Prasophyllum brevilabre that had not been seen in the past decade.

Searches failed to locate plants of Arthrochilus huntianus. The suspicion is that it is destroyed by fire and needs to recolonise from seed blown from unburnt areas.