L.S.,
Hopefully the collective knowledge of TFF community will once again prove able to identify something that has stumped me. This time I need your help with these curious stem fragments! A good friend of mine purchased these at a mineral show on the US mainland. The specimens potentially originate from Kane County, Utah, but this provenance is far from bulletproof. It is quite likely, however, that they come from somewhere within the USA. The stems exhibit a hollow centre, with a ribbed internal surface (pith structure?). None of the specimens show nodes or other signs of axial