Good point about stem colouration for decurrens, but this doesn't seem to be a typical locality. Surveys done in and around this part of Reserve (records in ALA) give several records for H. sericea and none for H. decurrens.
There has been significant confusion as to seperating out these two species so I wouldn't be surprised if that has played a factor here (this is even the case for the images used by the atlas of living Australia). As I understand it H.sericea is largely coastal (and uncommonly recorded south of Sydney), while H.decurrens is the common species on the tablelands. The flora at Nadgigomar Nature Reserve is evidently a mix of both given what else you've reported, so perhaps I've corrected unnecessarily. I take it this was on a Wednesday walk?
Thanks guys, good discussion. Yes the two are quite similar, I see a bit of both sides here, my confirmation was perhaps a little hasty. Though I was thinking along similar lines, H. sericea could be likely in this area, compared to most of the CNM area where H. decurrens is expected.
The ALA info was not based on photographs but was 'human observation' by NSW govt, which presumably means it was survey (ie quadrat) data; especially given the dates were mainly 2011 or thereabouts. And Yes, Nadgigomar Nat REs is indeed a transitional area
Gotcha, the vicflora key between these two isn't particuarly helpful in our case (Separation is based on floral features and the lignotuber). I'm wondering how we should resolve this. @RogerF any thoughts?
According to ALA which I have just looked up, decurrens is now restrictednto southern VIC and all decurrens in NSW are now sericea. Would you like to check/confirm this. Which one has the lignotuber?
According to PlantNet: sericea - no lignoturber decurrens - sometimes lignotuber. Just for completeness, there are three subspecies for decurrens, and lignotuber is NOT used to separae them (ie "sometimes" does not correspond to lignotuber)
ALA gives me a different take on relative distributions of sericea and decurrens from what you describe. My map (of records) shows no such clear separation, but instead shows a very solid overlap (virtually identical distribution) for sericea and decurrens in n-e Vic and in extreme s-e of NSW, and in NSW with decurrens extending further inland from GDR and sericea very solidly distributed from coast up and into southern ranges and tablelands.
(tried to create a QR of the map to paste in here . . . didn't work)