The New Zealand Plant Conservation Network

Hello. I've recently been working in both southern Fiordland and Stewart Island and have come across Celmisia plants which appear to my untrained eye to be very similar, if not the same (see series of photos). I found a few plants on Mt Anglem which have the classic clavate stems of C. clavata (photo 1), but the majority of plants I saw on both Mt Anglem, northern Stewart Island (photo 2) and Smiths Lookout, southern Stewart Island (photo 3) looked very similar to plants I saw on Mt. Aitkin, southern Cameron Mountains, Fiordland (photo 4). The leaf shape is very similar at all of these locations.
Are these truly distinct species or is their distinction mostly distribution based?
If they are distinct does anyone know if there any really solid features that can be used to tell them apart?

Thanks,
Rowan

Photo 2

Photo 3

Photo 3 again

Photo 4

Hi Rowan, it's a complicated one - all of C. clavata, C. sessiliflora, C. polyvena and C. argentea have been recorded (rightly or wrongly) from Stewart Is. The appearance of these species depends to some degree on growing condition, and sometimes they can be difficult to distinguish. They also are likely to hybridise (C. sessiliflora and C. argentea do this in Otago). A fuller collection and critical evaluation is needed. For my two cents photo 1 is C. clavata (Thomson emphasises the dead leaves being retained) and the other three look like C. argentea.

Wow, cool photos Rowan, thanks for sharing!

Hi Rowan, It is my view that Celmisia argentea is an eastern Otago species being found on the Rock and Pillars, Mangatuas, Blue Mountains Lamermoors etc. I am not entirely sure whether it extends inland to the Old Man Range or not. I have found plants on the Old Man Range that look like Celmisia argentea but others look like small forms of Celmisia sessiliflora. On the Rock and Pillars where I am most familiar with the plant Celmisia argentea seems to have very precise habitat requirements - a Goldilocks zone not to wet not too dry. Celmisia sessiliflora is also present confounding the issue with numerous hybrids with Celmisia argentea . Extending this line of reasoning to Stewart Island and making the assumption that Celmisia clavata is allopatric to Celmisia argentea you may well be observing Celmisia sessiliflora x Celmisia clavata hybrids. Photo 4 is possibly a small form of Celmisia sessiliflora or a hybrid of that species. Mike may beg to differ however.

Cheers Mike.
Sounds like I should collect a few herbarium specimens next time I'm out in these areas.
I also found this plant (see photo) growng on Mt Anglem. It looks like C. polyvena, and according to Hugh Wilson's 'Vegetation of Stewart Island' he did find some in that area, but accordind to the NZPCN page it only grows south of Mt Rakiahua.
Would anyone be willing to put a name to the photo? I have more leaf closeup ones if needed.

Cheers,
Rowan

Hi Rowan, it's not "classic" C. polyvena. Wilson does discuss a small version of C. polyvena and also hybrids with C. clavata. Your plant looks most similar to C. gracilenta (which i don't think is known from the island). Stewart Island botany has several unresolved issues surrounding identities and distribution and it is worth collecting material from there if it is flowering.