(scalariform-reticulate thickening) A type of * reticulate secondary wall patterning in * tracheary elements in which the network is broken by elongate unthickened areas arranged in a more or less parallel fashion. Whereas * annular thickening and * spiral thickening permit further elongation, reticulate and scalariform thickenings allow little further extension, and are therefore to be found in tissues, such as metaxylem and secondary xylem, that do not elongate after maturation. Compare pitted thickening. |
