Seems like it should be obvious. On moss covered log.
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No interactions present.
As Chris says the two species can look similar but I think X longipes is the best bet.
X.polymorpha will generally break towards its base when roughly handled. X.longipes rarely breaks and has a much more flexible "stem". As you noted the "stem" is little more than a slight diameter decrease towards base and is quite clear in your pictures.
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Lat/Lng: 54.980345, -1.753804
OS grid ref: NZ158651