Thanks Tony. There was a small population growing near the fire trail on the way to Cotter Hut, near the intersection with Yaouk Trail. I think we saw another population further south of the hut too. Wet peppermint forest, near a small stream.
What are the characteristics to look for that are the difference between decurvum and aestivum?
The main difference is that D. aestivum has a prominently protruding curved labellum when set. Also the flowers are slightly larger and more bulging than D. decurvum. They tend to grow in wetter areas often near streams.