Was the specimen in New Zealand bigger and older than the one you have now?

here are two photographs of one that I knew in New Zealand;

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and this is the one I bought here;

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- I don't think the difference between them is attributable to ontogenetic maturation. Fascicle morphology is different. Mine has one large primary branch, as well as the cluster of higher-order branches, and all branches of all orders are branched further, while the one in NZ has the 'pom-pom' fascicle morphology with no prominent primary branch, and the branches have little further branching. Also the branchlet tips on the NZ plant twist up towards the light, regardless of the orientation of the section of the culm they are on, while on mine they don't.

There is a similarly heterogeneous mix of different looking plants of this species on websites where different people contribute their own images of the same species, eg. Dave's Garden - and those ones are generally all mature clumps as well.

Peter

Where seedlings have been raised you'd expect some natural variation. And there's many species in the genus, of course, not everyone may all be showing correctly identified stock. Species names coronalis and coleau both start with the same letter, so it seems there is a basis right there for two species grown in western gardens for a long time to have gotten mixed up on occasion - as have cultivars of Platycladus (Thuja) orientalis and T. occidentalis (multiple letters in common probably making these two being confused especially likely) - as have others. It just takes someone mis-reading a partly faded or smeared tag, who doesn't know better. In some cases large quantities of plants are dispersed by commercial operations under the wrong names, for long periods of time.

Thanks for posting those Pictures Peter. To me (California grower of Chusquea) it looks like the one from NZ is actually C.cumngii, but it doesn't resemble the fine cascading leaves of coronailis at all. Here's C.cumngii grown in CA full sun under drought conditions.
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It might not be C.cumngii, but I don't think it's C.coronalis.

NZ = New Zealand?

Yep NZ= New Zealand.
I have a French book on bamboos that has pictures of the C.coronalis, and it's just like the one they sell here in the US. It does seem to be a little variable(after looking at web pics, but it's not as variable as the fist NZ pic you have)

Here is a link that might be useful: Chusquea coronalis

Here's C.cumingii in the US. The German version looks slightly different.

Here is a link that might be useful: C.cumingii