A stele consisting of a core of pith surrounded by concentric layers of xylem and phloem.
- ‘In anatomical cross section, the stem of Lepidodendron displays an exarch siphonostele surrounded by secondary xylem in ranks.’
- ‘The node cross section of Equisetum looks quite different: the siphonostele is complete and leaf traces emerge from the solid vascular cylinder only at these locations.’
- ‘Other lycophytes have a siphonostele, with a central region of generalized tissue within a cylinder of vascular tissue.’
- ‘Use the three-dimensional diagram to understand how a leaf gap relates to the vascular cylinder of a siphonostele.’
- ‘The thick-walled cells in the center of the core are sometimes considered to be pith, in which case the vascular arrangement would actually be a siphonostele.’
We take a look at several popular, though confusing, punctuation marks.