| Are there monocots in which primary xylem and early metaxylem are vesselless but metaxylem contains vessels? |
| They have narrow phloem strands adjacent to large, single, permanent protoxylem or metaxylem elements. |
| Protoxylem, early metaxylem, and late metaxylem could also be given separate scores on this basis. |
| Thus, if the carinal canals play a role in conduction, the metaxylem tracheary elements must be responsible for conduction across nodal regions. |
| Tracheary element secondary wall patterns and the definition of protoxylem and metaxylem. |
