At this time of the year, it is often only leaves that indicate the presence of our terrestrial orchids, and the appearance of orchid leaves is dependent upon the amount of rainfall that has occurred during summer and early autumn.
Chiloglottis reflexa Autumn Bird Orchid and C. trilabra Tall Bird Orchid are two species that grow in our area, and should be starting to show leaves at the present time, but the very dry conditions have certainly hampered their presence this year. All Chiloglottis species have distinctive, paired basal leaves, and you will usually find large colonies of leaves with very few flowers.
The flowers of the two species are very similar and can be extremely difficult to differentiate, but there a few main differences. If you look at the labellum on either species, you will notice that it is covered with a mass of shiny black glands, called calli. Both species have one, large stalked callus at the back of the labellum. The stalked callus in C. reflexa projects well above the other calli. It is distinctly notched at the tip.
However, if you view the labellum of C. trilabra from the side, you will notice that the large, stalked callus is lower, and generally in line with the calli mass. It has a shallow notch at the tip.
The mass of calli on C. trilabra extends to the apex of the labellum, while those of C. reflexa extend almost to the apex.
The lateral sepals are also an indicator of the species – those of C. reflexa are usually strongly recurved beneath the labellum, while those of C. trilabra usually hang more or less straight down. Good luck with your identification!
Other autumn orchids to start looking for in March are our three species of Midge Orchids, Corunastylis ciliata Fringed Midge Orchid, C. despectans Sharp Midge Orchid and C. morrisii Bearded Midge orchid; Eriochulus cucullatus Parson’s Bands; and the Tiny Greenhood Pterostylis parviflora.
Hopefully the autumn rains are not far away! Thanks to those people who have shared orchid finds over the summer months.