Diuris pardina

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Orchid people, could you id? we have Diuris nigromontana with a "?" on our Flora list - we have also D semilunulata and D pardina and perhaps hybrids (spotted before CNM but not confirmed).

Waltraud these are not easy. Of these 3 similar species there are as many similarities as differences. Possibly the biggest difficulty is the level of variation within species. We can have a clear idea what we think is each type but both colour and form variation continually challenges this. David Jones in first describing D. nigromontana outlined what he considered the main differences between it and D. semilunulata with a principle difference being the presentation with D. semilunulata presenting the dorsal sepal and the labellum, to appear much as the native pea flowers they mimic, with both the petals and lateral sepals folded back out of the way. Where D. nigromontana presents the petals and lateral sepals in the same plan as the dorsal sepal and labellum. While this is all great when the orchids follow the script the exceptions make it difficult. As I understand David (and Mark) consider D. semilunulata to be restricted more to the west of the city in areas like Mt Tennent, Nursery Swamp etc. (see 2008 Field Guide). D. nigromontana he considered to be around Black Mountain, Aranda, Bruce but included Majura Firing Range (but not Mt Majura)? D. pardina was considered more wide spread and the species along this north-eastern part of the city including Hall across to Kowen including Mts Majura & Ainslie, Gungahlin Hill, Mulligans Flat and the again the Firing Range. D. pardina is possibly the most varied in both colour and form and freely hybridizes with D. chryseopsis. I with the Orchid Society Conservation Group have been conducting a survey within Goorooyarroo for the past 12 months and have seen considerable variation in what we believe is D. pardina. Everything from pure yellow without markings through to very heavily marked with dark markings and along with every combination of hybrid imagined. It is hard to know where the variation ends and hybrid starts but it is possible find an example of what could many different species. I remain convinced the main species we see in this area is D. pardina but with much variability. D. sulphurea also in the area is not found to be variable in the same way and stays true to type.
While I see photos confirmed as other species in your area of interest I think only a directed review will establish the true species diversity from the species variability and we need to take a deep breath and acknowledge the difficulty and uncertainty our best efforts contain. It is very subjective without DNA.

Derek thanks heaps!

Confirmed - based on Derek's reasoning but see his reservations