1. 
   eustele
   When a plant's vascular tissue develops in discrete bundles, it is said to have a eustele. See also protostele and siphonostele.
   Found op http://www.ucmp.berkeley.edu/glossary/glossary_8.html
   
   
2. 
   eustele
   (from the article `fern`) ...the original fern stem was protostelic (its stele having no pith or leaf gaps), but this is not necessarily true of the immediate ancestor of ...
   Found op http://www.britannica.com/eb/a-z/e/54
   
   

Tip: double click on a word to show its meaning.